Strings of epitopes useful in diagnosing and eliciting immune responses to sexually transmitted infections

ABSTRACT

The invention provides methods and compositions for detecting and diagnosing sexually transmitted infections using a string of epitopes (SOE) specific for detection of causative microorganisms. The antigenic epitopes may be single epitope sequences, a plurality of epitope sequences joined by repeats of glycine (-GG-) and/or lysine (-KK-) to form a series of epitopes (SOE), or nucleotide sequences encoding one or more SOEs and host cells harboring said SOE nucleotide sequences. SOEs specific for highly immunogenic regions of proteins from  Trichomonas, Treponema  and  Neisseria  species are provided. SOEs to detect the presence of  trichomonas  species comprise regions from  Trichomonas -sptciric aldolase, GAPDH, a-enolase and a-actinin proteins. Pharmaceutical compositions comprising SOEs can also be used as vaccines or to elicit an immune response to specific microorganisms.

The invention relates to compositions methods used to detect and/or diagnose infections caused by, for example, Trichomonas, Treponema, and Neisseria species. The invention further relates to compositions and methods for eliciting an immune response and/or vaccinating against infection by Trichomonas, Treponema, and Neisseria species

BACKGROUND OF THE INVENTION

Sexually transmitted infections (STIs) are a major global cause of acute illness, infertility, long term disability and death, with severe medical and psychological consequences for millions of men, women and infants. WHO estimated that 340 million new cases of syphilis, gonorrhoea, chlamydia and trichomoniasis occurred throughout the world in 1999 in men and women aged 15-49 years, and incidence has risen steadily since then.

Trichomonas vaginalis causes vaginitis in women and non-gonococcal, non-chlamydial urethritis in men. Among men, the most recent findings indicate a relationship between seropositivity to T. vaginalis and prostate cancer. This parasite is now the number one, non-viral sexually transmitted disease agent. In 2013, the incidence of this sexually transmitted infection (STI) referred to as trichomonosis or trichomoniasis is estimated to be 10 million women in the United States and 270 to 350 million women worldwide. Health consequences to women include cervical cancer, pelvic inflammatory disease, infertility, increased HPV and herpes susceptibility, and adverse pregnancy outcomes accompanied with low-birth-weight infants. Significantly, 25% of HIV seroconversions are the direct result of trichomonosis, which is known to increase the portal of exit and entry of HIV infectious viral particles. Therefore, control of trichomonosis may be one of the most effective means of reducing HIV transmission risk and of preventing prostate and cervical cancers worldwide.

It is clear that the public health costs as a result of this STI are enormous, and interference strategies are needed. The most important interference strategy is the availability of rapid, accurate diagnostics with exceptional sensitivity and specificity toward this STI agent. Despite the impact of this STI to public health, fundamental aspects of T. vaginalis cell biology and mechanisms of pathogenesis remain unknown. As previously disclosed in U.S. Pat. No. 8,017,103 B2, α-actinin is expressed by Trichomonas species and can be used to detect the presence of Trichomonas infection. However, the antibodies to parasite proteins available hitherto are inferior in their ability to detect the immunoreactive trichomonad protein antigens.

SUMMARY OF THE INVENTION

The antibodies, proteins, and epitopes to the proteins detected by the human antibody of the present invention are novel and have increased utility for diagnostics to this STI. Antigenicity and specificity is increased with the microorganism-specific target protein antigens and epitopes of the present invention compared to previously available diagnostics. Furthermore, the present invention overcomes prior shortcomings in the art by providing epitopes for detecting antibody in sera of humans exposed to and/or infected with T. vaginalis and other microorganisms that cause STIs, such as Treponema pallidum and Neisseria gonorrhoeae. In addition to compositions and methods relating to detection and diagnosis of STIs, the invention includes compositions and methods for eliciting an immune response and providing vaccines that can protect subjects from STIs.

An embodiment of the invention is a method of detecting the presence of a microorganism in a biological sample from a subject, comprising the steps of identifying at least one protein that is expressed by the microorganism of interest, determining regions of the protein that are highly immunogenic, and designing 15-mer epitopes encoding those regions. The invention is further directed to synthesizing a plurality of 15-mer epitopes in a linear array to form a series of epitopes (SOE), wherein the 15-mer epitopes are joined with amino acid repeats of glycine (-GG-) or lysine (-KK-). The SOE is then contacted with a biological sample under conditions whereby an antigen-antibody complex can form, and formation of at least one said antigen-antibody complex is an indication of the presence of the microorganism of interest. The SOE typically comprises at least six of said 15-mer epitopes, but may comprise fewer or greater numbers of 15-mer epitopes. A composition may comprise SOEs to detect multiple proteins from a single species or family of microorganisms, or from a group of unrelated microorganisms.

Sequences encoding 15-mer epitopes and SOEs are provided to detect, diagnose or treat infections caused by Trichomonas, Treponema, and Neisseria species. Aspects of the invention are applicable to other species. Exemplary SOEs detect Trichomonas species including Trichomonas (T.) vaginalis, T. vaginalis isolates T016, T068-II, UT40, and VB102, Tritrichomonas (Tt.) foetus, T. foetus, Tt enteris, T. paviovi, Tt. suis, Tt. Rotunda, T. buttreyi, Tt. Ovis, Tt. Equi, T. equibuccalis, T. anatis, Tt. eberthi, T. gallinae, T. gallinarum, Tt. caviae, Tt marls, Tt. wenoni, Tt. Minuta, T. microti, T. canistomae, T. felistomae, T. tenax, Tt. hominis, and T. macacovaginae. Epitopes, 15-mer epitopes and SOE sequences are provided to detect diagnose or treat infections caused by Treponema pallidum and Neisseria gonorrhoeae.

Additional bacterial pathogens may be detected, diagnosed, or vaccinated against, with SOEs encoding highly immunogenic regions of one or more proteins expressed by a microorganism or bacterial pathogen of interest. Other microorganisms include, but are not limited to Chlamydia trachomatis, Saccharomyces cerevisiae, Candida albicans, Streptococcus pyogenes, Streptococcus pneumoniae, and Staphylococcus aureus.

In one embodiment, detection is performed by immunoassay. A preferred immunoassay is an enzyme-linked immunosorbent assay (ELISA). The preferred biological sample can be saliva, urine, blood, serum or plasma, a lung lavage or sputum sample, and the subject may be male or female. Biological samples can also be vaginal fluid or washing, or semen or prostatic fluid.

In some embodiments, the biological sample is cerebrospinal fluid, joint fluid, body cavity fluid, whole cells, cell extracts, tissue, biopsy material, aspirates, exudates, pap smear samples, pap smear preparations, slide preparations, fixed cells, and tissue sections. The biological samples can be collected from a subject that may be human, non-human primate, dog, cat, cattle, sheep, swine, horse, bird, mouse and rat.

In one exemplary embodiment, a method of diagnosing a Trichomonas infection in a subject, comprises the steps of identifying at least one protein that is expressed by a Trichomonas species, determining one or more regions of at least one protein from Trichomonas that is/are highly immunogenic, designing 15-mer epitopes encoding said regions the protein, and synthesizing a plurality of 15-mer epitopes in a linear array to form a series of epitopes (SOE) wherein the 15-mer epitopes are joined with glycine (-GG-) and/or lysine (-KK-) repeats. Any SOE may contain a mixture of both -GG- and -KK- repeats. A biological sample from a subject is contacted with at least one SOE that binds an antibody to a Trichomonas-specific protein selected from the group consisting of aldolase, GAPDH, α-enolase and α-actinin, under conditions whereby an epitope-antibody complex can form, and detecting formation of at least one epitope-antibody complex as an indication of Trichomonas infection. The biological sample typically is serum, plasma, blood, saliva, semen, cerebrospinal fluid, semen, prostatic fluid, urine, sputum, joint fluid, body cavity fluid, whole cells, cell extracts, tissue, biopsy material, aspirates, exudates, vaginal washings, pap smear samples, pap smear preparations, slide preparations, fixed cells, or tissue sections. The method of detecting the epitope-antibody is performed using an immunoassay. In one exemplary embodiment, the immunoassay is an enzyme-linked immunosorbent assay (ELISA). The Trichomonas species that can be identified include Trichomonas (T.) vaginalis, T. vaginalis isolates T016, T068-II, UT40, and VB102, Tritrichomonas (Tt.) foetus, T. foetus, Tt enteris, T. paviovi, Tt. suis, Tt. Rotunda, T. buttreyi, Tt. Ovis, Tt. Equi, T. equibuccalis, T. anatis, Tt. eberthi, T. gallinae, T. gallinarum, Tt. caviae, Tt muris, Tt. wenoni, Tt. Minta, T. microti, T. canistomae, T. felistomae, T. tenax, Tt. hominis, and T. macacovaginae. A subject in this invention is any animal that can be infected by trichomonads. In certain embodiments, the subject is human.

An exemplary embodiment includes a method of diagnosing in a subject a sexually transmitted infection (STI) selected from the group consisting of trichomoniasis, gonorrohoeae, and syphilis. This embodiment involves the steps of identifying at least one protein that is expressed by the microorganism of interest, determining regions of at least one protein that is highly immunogenic, designing 15-mer epitopes encoding the highly immunogenic regions of the protein, and synthesizing a plurality of said 15-mer epitopes in a linear array to form a series of epitopes (SOE) wherein the 15-mer epitopes are joined with amino acid repeats of glycine (-GG-) and/or lysine (-KK-). Variations on this method further comprise assaying biological samples from a subject that are collected at two different time points. The interval of time may be days, weeks, or months, as deemed appropriate by one of ordinary skill in the art of STI diagnosis. The assay can be an immunoassay, with at least one SOE encoding at least one protein specific to one or more microorganisms suspected of causing a STI, under conditions whereby an epitope-antibody or antigen-antibody complex can form; and detecting formation of at least one epitope-antibody complex in the two samples. Detection readout at the first time point is compared with detection readout of the second time point and the comparison is used to determine the status of a STI in said subject.

Embodiments of the invention include a monoclonal antibody selected from the group of ALDwsu-1, ALDwsu-2, ALD12A, ALD64A, B44, ENOwsu-2, ENOwsu-3, ENOwsu-4, ENOwsu-6, B43, GAPwsu-2, GAPwsu-3, and HA423 (Tables 1 and 2A).

Embodiments also include an epitope selected from the group consisting of SEQ ID NO:1-53, 66-78, 104-106, 121-126, 139-143 and 162-165; or 15-mer epitope selected from the group consisting of SEQ ID NO:79-102, 107-119, and 128-133. The invention is further a string of epitopes (SOE), comprising a plurality of epitopes linked by glycine or lysine repeats (-GG- or -KK-), selected from the group consisting of SEQ ID NO:120, 127, 134, 145, and 146.

Embodiments further include a nucleic acid encoding at least one epitope, or at least one 15-mer epitope, or at least one string of epitopes (SOE), wherein the protein product of the nucleic acid binds to at least one antibody type in a biological sample and at least one antibody type is reactive with at least one Trichomonas protein selected from the group consisting of aldolase, alpha-enolase, GAPDH, and alpha-actinin.

Embodiments also include a host cell comprising a transgene encoding a string of epitopes (SOE), wherein the SOE comprises a plurality of epitopes selected from NO:1-53, 66-78, 104-106, 121-126, AND 139-143, or a plurality of 15-mer epitopes selected from the group consisting of SEQ ID NO:79-102, 107-119, AND 128-133, wherein each SOE binds to at least one antibody type in a biological sample and the antibody type is reactive with at least one protein from a microorganism of interest. For Trichomonas, the protein is selected from the group consisting of aldolase, alpha-enolase, GAPDH, and alpha-actinin.

In addition, embodiments include a kit for diagnosis of a sexually transmitted infection (STI) in a subject, comprising at least one string of epitopes (SOE) able to bind at least one antibody type in a biological sample that is reactive with at least one protein from a microorganism selected from the group consisting of Trichomonas, Treponema, and Neiserria species, The kit comprises one or more reagents to perform an immunoassay of antibody-epitope or antibody-antigen complexes that form when the SOE of the kit contacts at least one antibody type in a biological sample, and may include a suitable vessel for performing said immunoassay, and a package insert describing steps required for performing said immunoassay, wherein detection of an antibody epitope or antibody-antigen complexes is diagnostic for a STI.

Embodiments also include eliciting an immune response to a microorganism in a subject. These involve identifying at least one protein that is expressed by the microorganism, determining regions of said at least one protein that are highly immunogenic, designing 15-mer epitopes encoding said regions of said at least one protein, and synthesizing a plurality of said 15-mer epitopes in a linear array to form a series of epitopes (SOE) wherein said 15-mer epitopes are joined with amino acid repeats selected from the group of glycine (-GG-) and lysine (-KK-). A pharmaceutical composition preferably includes at least one SOE with a suitable carrier and adjuvant, which is administered to a subject in an amount sufficient to stimulate formation of antibodies to the SOE by the immune system of the subject.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are provided to assist in the understanding of the invention, but do not the limit the invention and its uses.

FIG. 1 shows an ELISA assay of trichomonads to detect T. vaginalis aldolase, GAPDH, and α-enolase.

FIG. 2 shows detection of T. vaginalis using different amounts of individual MAbs to show specificity of the MAbs.

FIGS. 3A, 3B, and 3C show sequence alignment of fructose-1,6-bisphophate aldolase sequences from T. vaginalis, T. pallidum, N. gonorrhoeae, S. pyogenes, S. pneumoniae, S. aureus, E. coli, C. albicans, Saccharomyces cerevisiae and Homo sapiens.

FIG. 4A shows hydrophobicity and antigenicity profile of T. vaginalis α-enolase (ENO).

FIG. 4B shows hydrophobicity and antigenicity profile of T. vaginalis fructose-1,6-bisphosphate aldolase (ALD).

FIG. 4C shows hydrophobicity and antigenicity profile of T. vaginalis α-glyceraldehyde-3-phosphate dehydrogenase (GAP).

FIGS. 5A, 5B, 5C, and 5D show representative dot blots of individual 15-mer peptide epitopes.

FIG. 6A shows representative duplicate dot blots of combinations of 15-mer epitopes.

FIG. 6B shows densitometric scans of reactive dot blots from FIG. 4A.

FIG. 7A shows the 111 amino acid sequence of an rSOE encoding 15-mer epitopes of GAP (GAPDH), ENO (enolase) and ALD (aldolase) proteins from T. vaginalis. The sequence is that of SEQ ID NO:145.

FIG. 7B shows SDS-PAGE and Coomassie-brilliant blue stained gels of recombinant E. coli, rSOE lysate, flow-through, washes and elution fractions.

FIG. 8A shows immunodetection of rSOE by ELISA.

FIG. 8B shows immunodetection of rSOE by dot blot.

FIG. 8C shows immunodetection of rSOE by immunoblotting after SDS-PAGE.

FIG. 9 is an example of an SOE comprising thirteen epitopes detected by women and men exposed to T. vaginalis are arranged sequentially within individual 15-mer peptides separated by a diglycine. The sequence is that of SEQ ID NO:146.

FIG. 10 shows immunoblot detection of ACT-P2 using IgG1 MAb HA423 and positive control sera from women and men.

FIGS. 11A and 11B are gels showing that pooled positive control sera from both women and men are unreactive with HuACTNa and have antibodies to numerous trichomonad proteins.

FIGS. 12A-12G show SPOTs analysis with positive control sera from women and men, detecting overlapping peptides on SPOTs membranes of a representative epitope and reactions with immobilized ACT-P2 and synthetic 15-mer peptides used in combination or singly. 12A shows IgG antibody detection of overlapping peptides from spots 214-217. 12B shows the corresponding amino acid sequences of the individual oligopeptides (SEQ ID NO:162-165). 12C and 12D show signal intensities obtained for 1 microgram of ACT-P2 or 2/13M5+W10/M2 immobilized on nitrocellulose membranes and detected by IgG of positive control sera. 12E shows densitometric scans of the dots shown in C2 to provide relative intensities. 12F shows relative reaction of 1 μgram of 15-mer epitopes from Table 1, immobilized on nitrocellulose membranes. 12G shows denitometric scans to provide relative intensities of dots.

FIG. 13 shows a hydrophobicity plot for T. vaginalis α-actinin.

FIGS. 14A, 14B, 14C, and 14D show an amino acid sequence alignment of T. vaginalis α-actinin (SEQ ID NO:157) with representative pathogenic organisms T. suis, C. albicans, S. cerevisiae and HuACTN1.

DETAILED DESCRIPTION

The present invention comprises peptide and nucleotide sequences encoding peptides that are highly immunogenic and may be used to detect the presence of microorganisms in a biological sample, or diagnose an infection of the microorganisms in a subject. The methods of the invention can comprise detection of one or more microorganism-specific proteins in one or more biological samples, or detection of antibodies that a subject has produced in response to exposure or infection caused by microorganisms. The invention further comprises compositions and methods for eliciting an immune response in a subject, or vaccinating against a STI, such as trichomoniasis, gonorrohea or syphilis.

The invention further comprises methods of arraying the highly immunogenic peptides in a linear macromolecule described herein as a series of epitopes (SOE), recombinant series of epitopes (rSOE), or string of pearls (SOP). In one embodiment, an SOE is synthetic DNA encoding a protein comprising sequential 15-mer peptides. The DNA encoding the SOE can be ligated into a plasmid and used to transform or transfect a suitable host cell that will express the SOE as a recombinant protein. In another embodiment, an SOE can be synthesized as a polypeptide sequence encoding sequential 15-mer peptides. Amino acid repeats of glycine (-GG-) or lysine (-KK-) are placed between the 15-mer peptides, either encoded as nucleotides in DNA, or as amino acid residues in a synthetic polypeptide. Typically, at least six 15-mer epitopes linked with -GG- or -KK- are used, however, more 15-mers may be added to a synthetic DNA construct or to a synthetic peptide. In another embodiment, several SOE species may be included in a composition. Each of the SOE species may differ in the identity of the 15-mer epitopes included in each, or they may further be 15-mer epitopes from different proteins or even different microorganisms.

The invention is based on the unexpected discovery that infection with T. vaginalis and other Trichomonas species can be diagnosed by detecting individually or in combination T. vaginalis or other Trichomonas species aldolase, GAPDH, α-enolase and/or α-actinin proteins or epitopes of the proteins either singly or in combination and/or antibodies to AGEA proteins or epitopes of the proteins either singly or in combination. Similar to embodiments relating to T. vaginalis, further embodiments of the invention are methods of detecting, diagnosing or preventing infection of N. gonorrohoeae and/or T. pallidum. These embodiments make use of highly immunogenic 15-mer peptides and SOEs that elicit an immune response to either N. gonorrohoeae or T. pallidum, and sequence listings are provided for each of the microorganisms of interest. Each of the embodiments of the invention may be practiced by substituting the SOE or antibodies specific to a microorganism of interest, such as a species of the trichomonas, neiserria or treponema families. Further, amino acid sequences of other sexually transmitted bacterial pathogens (Chlamydia trachomatis), of yeast (Saccharomyces cerevisiae and Candida albicans), and of other human bacterial pathogens (Streptococcus pyogenes, Streptococcus pneumoniae, and Staphylococcus aureus) may be identified and incorporated into SOEs for detection and diagnosis, and may also be used to elicit immune response and provide protection from infection.

Thus, in some embodiments, the present invention provides a method of diagnosing a T. vaginalis infection in a subject. Highly immunogenic regions of microorganism-specific proteins selected from the group consisting of T. vaginalis aldolase, GAPDH, α-enolase and/or α-actinin are identified and at least one SOE comprising 15-mer peptides encoding the highly immunogenic regions. The 15-mer peptides are linked with -GG- or -KK- amino acids. A biological sample from the subject suspected of having an infection caused by the T. vaginalis under conditions whereby an antigen/antibody complex can form; and b) detecting formation of an antigen/antibody complex, thereby detecting T. vaginalis AGEA proteins or epitopes of the proteins either singly or in combination in the sample and thereby diagnosing a T. vaginalis infection in the subject.

Additionally provided is a method of identifying an acute T. vaginalis infection in a subject, comprising: a) at a first time point, contacting a first sample from the subject with a T. vaginalis protein selected from a) aldolase, GAPDH, α-enolase and/or α-actinin proteins or epitopes of proteins either singly or in combination, under conditions whereby an antigen/antibody complex can form; b) detecting the formation of an antigen/antibody complex in step a); c) at a second time point, contacting a second sample from the subject with a T. vaginalis protein or epitopes of proteins selected from aldolase, GAPDH, α-enolase and/or α-actinin proteins, under conditions whereby an antigen/antibody complex can form; d) detecting the formation of an antigen/antibody complex in step (c); and e) comparing the amount of antigen/antibody complex of step (b) with the amount of antigen/antibody complex of step (d), whereby a difference in the amount of antigen/antibody complex identifies an acute T. vaginalis infection in the subject.

Typically, the biological samples used in practicing the invention are vaginal washings, pap smear or other cell preparations, urine, blood or serum, or saliva samples. However, the sample in all the above various embodiments of the invention can be any biological fluid or tissue that can be used in an immunoassay that either detects antibody in the biological fluid or detects protein in the biological fluid with available polyclonal and/or monoclonal antibodies to the proteins of this invention, including but not limited to, lung aspirates, semen, cerebrospinal fluid, semen, prostatic fluid, sputum, joint fluid, body cavity fluid, whole cells, cell extracts, tissue, biopsy material, aspirates, exudates, vaginal washings, pap smear samples, pap smear preparations, slide preparations, fixed cells, or tissue sections from a subject, where the subject can be either female or male. Several recent reports examining infections in the lungs of immunocompromised individuals or patients with acute respiratory distress syndrome have shown the presence of T. vaginalis as primary or secondary infection. Therefore, it is understood that the invention may be useful for diagnosis and treatment of patients regardless of STI status, and that any biological sample may be used.

In the embodiment of identifying an acute infection in a subject, a first sample is taken at a first time point and a second sample is taken at a second time point and the amount of antibody or antigen and/or the type of antigen or antibody present in the two samples is compared. A change in the amount and/or type of antibody or antigen is indicative of an acute infection and no change in the amount and/or type of antibody or antigen is indicative of a past or chronic infection. For example, a decrease in the amount of antibody or antigen in the sample taken at the second time point (e.g., after treatment of the subject for a T. vaginalis infection) is indicative that the infection at the time the first sample was taken was an acute infection. Furthermore, if there is an increase in titer of antibody or amount of antigen, this would indicate an ongoing/active infection that was not diagnosed initially or that was not eliminated upon diagnosis and drug treatment. This would necessitate additional examination of body sites and tissues for the presence of organism or antigen or antibody.

Furthermore, a T. vaginalis protein of this invention can detect, but is not limited to, a recombinant α-enolase, aldolase, GAPDH and/or α-actinin protein as described in the EXAMPLES section set forth herein, as well as peptides of the reactive epitopes, fragments, and immunologically-similar variants of such proteins, peptides and fragments. Such epitopes and recombinant proteins and peptides of this invention can be produced according to methods well known in the art and can also be produced by fractionation and/or isolation techniques, synthesis techniques, etc. that are known for producing proteins and peptides for use in immunoassays.

The term “Trichomonas” as used herein, includes, but is not limited to a protozoan parasite of the order Trichomonadida, genera Ditrichomonas, Trichomonas, Tritrichomonas and Pentatrichomonas, comprising multiple species that infects both humans and animals. “Trichomonas” refers to any Trichomonas species, e.g., Tritrichomonas foetus (also known as Trichomonas foetus, Tt. fetus), Tt enteris and T. paviovi, which infect cattle; Tt. suis, Tt. rotunda and T. buttreyi, which infect swine; Dt. Ovis, which infects sheep; Tt. equi and T. equibuccalis, which infect horses; T. anatis, Tt. eberthi, T. gallinae and T. gallinarum, which infect birds; Tt. caviae, Tt muris, Tt. wenoni, Tt. Minuta and T. microti, which infect rodents; T. canistomae and T. felistomae, which infect dogs and cats; and T. tenax, T. vaginalis, Pt. hominis, and T. macacovaginae, which infect primates (including humans). Trichomonas vaginalis as described herein includes isolates T016, T068-II, UT40, and VB102, as well as any other T. vaginalis isolate now known or later identified.

The term “antibody” as used herein, includes, but is not limited to a polypeptide encoded by an immunoglobulin gene or immunoglobulin genes, or fragments thereof. An antibody may be produced in a species other than the species of the subject putatively affected by a Trichomonas infection. “Antibody” also includes, but is not limited to, a polypeptide encoded by an immunoglobulin gene or immunoglobulin genes, or fragments thereof, which specifically binds to and recognizes the antigen-specific binding region (idiotype) of an antibody produced by the host in response to exposure to T. vaginalis or other Trichomonas species antigen(s). Antibodies may also be produced using recombinant DNA gene engineering to generate synthetic linear or conformational antibodies that recognize and bind to their cognate antigen(s).

The term “epitope” means an antigenic determinant that is specifically bound by an antibody. Epitopes usually consist of surface groupings of molecules, such as amino acids and/or sugar side chains, and may be linear or have specific three-dimensional structural characteristics, as well as specific charge characteristics.

The term “15-mer epitope” and “15-mer amino acid sequences” are used interchangeably to describe the building blocks of a “series of epitopes” (see definition of series of epitopes below). A 15-mer epitope typically comprises are typically peptide 15-mers comprising 5 to 11 residues which are highly immunogenic. The epitope must have enough amino acid residues so that the peptide product is large enough to be recognized, which will generally be at least 4-5 amino acids, but can be up to 11, 12, 13, 14, or at least 15 amino acids. The peptide 15-mers encode highly immunogenic epitope regions (from a protein expressed by a pathogenic microorganism of interest), flanked by 3 to 5 amino acids of naturally occurring sequence in order to mimic the tertiary structure of protein folding to recapitulate the native protein domain. These sequences are also called 15-mer epitopes in order to distinguish them from the epitope within the native protein. However, they could easily be made small or larger, generally within the range of 5 to 30 amino acids, 10 to 25 amino acids, or 12 to 20 amino acids. Those of skill in the art will recognize that 15 amino acids is considered to be a starting point or “default” size for designing short peptide sequences of epitopes. A 15-mer is thought to be sufficiently large enough to allow correct folding and presentation of an immunogenic site or protein domain, without having extraneous free ends that might hinder access to the site of interest. It can be easily understood that a 14-mer, 16-mer, or any other oligopeptide of about 5-30 amino acids could also be used in practicing the invention, so long as it comprises the essential core of the immunogenic amino acids provided in each sequence of the invention, shown in various tables herein, and is functionally immunogenic.

The terms “series of epitopes” or “string of epitopes” (SOE), “recombinant series of epitopes” (rSOE), and “string of pearls” (SOP) are used interchangeably to refer to a synthetic macromolecule encoding a plurality of epitopes. The epitopes encoded in the SOE, rSOE, or SOP macromolecules of the invention are typically peptide 15-mers (or 15-mer amino acid sequences) comprising 5 to 11 residues which are highly immunogenic. Selection of epitopes and/or 15-mer epitopes to be included in a SOE is based specificity of the sequence, i.e., having no identity to other proteins in databases. This is especially true with the SOEs that have epitopes and/or 15-mer epitopes from proteins expressed by other organisms. Thus, selecting unique sequences helps to eliminate false positives that may occur due to recognition of proteins or antibodies to proteins from other organisms. The plurality of epitopes are typically arrayed in a linear molecule linked with repeats of glycine (-GG-), lysine (-KK-), or a mixture of both. rSOE protein can be expressed in host cells transfected or transformed with a vector carrying a nucleic acid encoding SOE or SOP sequences.

The term “highly immunogenic” means that the amino acids encoded by the sequences indicated will selectively and specifically bind to antibodies raised against a particular sequence. For example, the epitopes, 15-mer epitopes, and SOEs of the invention from regions of T. vaginalis α-actinin will detect the presence of T. vaginalis antibodies in in vitro detection assays. Accordingly, antibodies raised against the epitopes, 15-mer epitopes, and SOEs of the invention from regions of T. vaginalis α-actinin will detect the presence of T. vaginalis α-actinin protein or protein fragments.

The terms “specifically binds to” and “specifically reactive with” refer to a binding reaction that is determinative of the presence of the antigen and antibody in the presence of a heterogeneous population of proteins and other biologics. Thus, under designated assay conditions, the specified antibodies and antigens bind to one another and do not bind in a significant amount to other components present in a sample. Specific binding to a target analyte under such conditions may require a binding moiety that is selected for its specificity for a particular target analyte. A variety of immunoassay formats may be used to select antibodies specifically reactive with a particular antigen. For example, solid-phase enzyme-linked immunosorbent assays (ELISA) are routinely used to select monoclonal antibodies specifically immunoreactive with an analyte. See Harlow and Lane (ANTIBODIES: A LABORATORY MANUAL, Cold Springs Harbor Publications, New York, (1988)) for a description of immunoassay formats and conditions that can be used to determine specific immunoreactivity. Typically a specific or selective reaction will be at least twice background signal to noise and more typically more than 10 to 100 times greater than background.

An “immunologically reactive fragment” of a protein refers to a portion of the protein or peptide that is immunologically reactive with a binding partner, e.g., an antibody, which is immunologically reactive with the protein itself.

As used herein, and “antibody-antigen complex” can refer to an immune complex that forms when an antibody binds to its preferred or recognized antigen. The antigen may be a full-length native protein, or it may be a protein fragment, either naturally occurring or synthetic. The antigen may further be an epitope, and that epitope may be synthetic. As practiced in the invention, and antigen may further be a 15-mer epitope or an SOE, as defined above. As disclosed herein, a discussion of antibody-epitope complex may further mean a complex of one or more 15-mer eptiopes or SOEs and one or more antibody types. An immune complex comprising an antibody and an epitope may also be referred to as an antibody-epitope complex to distinguish if from an antibody-antigen complex, however, both antibody-epitope complexes and antibody-antigen complexes can be collectively referred to as immune complexes.

As used herein, the term “vaccine” refers to a composition the may be used to treat an individual to provide protection against challenge, and more specifically it provides protection against a challenge mounted by exposure to or infection with a microorganism. For example, an SOE composed of an array of T. vaginalis epitopes in a solution suitable for injection into a subject may provide protection from trichomoniasis. An SOE comprising an array of N. gonorrohoeae epitopes may provide protection from gonorrohea, and an SOE comprising an array of T. pallidum epitopes may provide protection from syphilus.

As used herein, the term “immunogenic composition” refers to a composition comprising a SOE, rSOE, and/or SOP composed of epitopes that elicit an immune response. For example, an SOE composed of an array of T. vaginalis epitopes in a solution suitable for injection into a subject may elicit an immune response to T. vaginalis infection. An SOE comprising an array of N. gonorrohoeae epitopes may elicit an immune response to N. gonorrohoeae infection, and an SOE comprising an array of T. pallidum epitopes may elicit an immune response to T. pallidum infection.

Antibodies to T. vaginalis proteins can be generated using methods that are well known in the art. Such antibodies can include, but are not limited to, polyclonal, monoclonal, chimeric, humanized, single chain, Fab fragments, and fragments produced by an expression library, including phage display. (See, e.g., Paul, FUNDAMENTAL IMMUNOLOGY, 3rd Ed., 1993, Raven Press, New York, for antibody structure and terminology.)

Antibody fragments that contain specific binding sites for a T. vaginalis protein can also be generated. For example, such fragments include, but are not limited to, the F(ab′)₂ fragments that can be produced by pepsin digestion of the antibody molecule, and the Fab fragments that can be generated by reducing the disulfide bridges of the F(ab′)₂ fragments. Alternatively, Fab expression libraries can be constructed to allow rapid and easy identification of monoclonal antibody Fab fragments with the desired specificity (Huse et al., Science 254, 1275-1281 (1989)).

For the production of antibodies, various hosts including goats, rabbits, rats, mice, humans, and others, may be immunized by injection of chemically-stabilized whole organisms or any extract or lysate of organisms comprising total proteins or with a T. vaginalis protein (e.g., individual or a combination of aldolase, GAPDH, α-enolase and/or α-actinin proteins) or any fragment or oligopeptide or conjugate thereof that has immunogenic properties. In practicing the invention, one or more epitopes, 15-mer epitopes and.or SOEs may be used for injection into hosts for the production of antibodies. Depending on the host species, various adjuvants can be used to increase the immunological response. Such adjuvants include, but are not limited to, Freund's complete and incomplete adjuvant, mineral gels such as aluminum hydroxide, and surface active substances such as lysolecithin, pluronic polyols, polyanions, peptides, oil emulsions, keyhole limpet hemocyanin, and dinitrophenol. Examples of adjuvants used in humans include BCG (bacilli Calmette-Guerin) and Corynebacterium parvum.

Monoclonal antibodies (MAbs) to Trichomonas vaginalis proteins can be prepared using any technique that provides for the production of antibody molecules by continuous cell lines in culture. These include, but are not limited to, the hybridoma technique, the human B-cell hybridoma technique, and the EBV-hybridoma technique (Kohler, et al. (1975) Nature 256:495-497; Kozbor, et al. (1985) J. Immunol. Methods 81:31-42; Cote, et al. (1983) Proc. Natl. Acad. Sci. 80:2026-2030; Cole, et al. (1984) Mol. Cell Biol. 62:109-120). Briefly, the procedure is as follows: an animal is immunized with a T. vaginalis protein, such as individual or a combination of aldolase, GAPDH, α-enolase and/or α-actinin proteins, or immunogenic fragment or oligopeptide or conjugate thereof. For example, haptenic oligopeptides of a T. vaginalis protein can be conjugated to a carrier protein to be used as an immunogen. Lymphoid cells (e.g., splenic lymphocytes) are then obtained from the immunized animal and fused with immortal cells (e.g., myeloma or heteromyeloma) to produce hybrid cells. The hybrid cells are screened to identify those that produce the desired antibody.

Human hybridomas that secrete human MAb can be produced by the Kohler and Milstein technique. Although human antibodies are especially preferred for treatment of humans, in general, the generation of stable human-human hybridomas for long-term production of human MAb can be difficult. Hybridoma production in rodents, especially mouse, is a very well established procedure and thus, stable murine hybridomas provide an unlimited source of antibody of select characteristics. As an alternative to human antibodies, the mouse antibodies can be converted to chimeric murine/human antibodies by genetic engineering techniques. See Oi, et al., Bio Techniques 4(4):214-221 (1986); Sun, et al., Hybridoma 5 (1986).

The MAbs of this invention specific for T. vaginalis protein epitopes can also be used to produce anti-idiotypic (paratope-specific) antibodies. (See e.g., McNamara et al., Science 220,1325-26 (1984); Kennedy et al., Science 232:220 (1986).) These antibodies resemble the T. vaginalis protein epitope and thus can be used as an antigen to stimulate an immune response against the T. vaginalis protein.

In addition, techniques developed for the production of “chimeric antibodies,” the splicing of mouse antibody genes to human antibody genes to obtain a molecule with appropriate antigen specificity and biological activity can be used (Morrison, et al., Proc. Natl. Acad. Sci. 81:6851-6855 (1984); Neuberger, et al., Nature 312:604-608 (1984); Takeda, et al., Nature 314:452-454 (1985)). Alternatively, techniques described for the production of single chain antibodies can be adapted, using methods known in the art, to produce T. vaginalis protein-specific single chain antibodies. Antibodies with related specificity, but of distinct idiotypic composition, can be generated by chain shuffling from random combinatorial immunoglobin libraries (Burton, Proc. Natl. Acad. Sci. 88:11120-3 (1991)). Antibodies can also be produced by inducing in vivo production in the lymphocyte population or by screening immunoglobulin libraries or panels of highly specific binding reagents as described in the literature (Orlandi, et al., Proc. Natl. Acad. Sci. 86:3833-3837 (1989)); Winter, et al., Nature 349:293-299 (1991)).

Various immunoassays can be used to identify antibodies of this invention having the desired specificity. Furthermore, a wide variety of immunoassays may be employed in the methods of this invention to detect antibodies and antigens of T. vaginalis proteins for diagnosis of T. vaginalis infection. Such immunoassays typically involve the measurement of antigen/antibody complex formation between a T. vaginalis protein or peptide and its specific antibody.

The immunoassays of the invention can be either competitive or noncompetitive. In competitive binding assays, T. vaginalis antigen or antibody competes with a detectably labeled T. vaginalis antigen or antibody for specific binding to a capture site bound to a solid surface. The concentration of labeled antigen or antibody bound to the capture agent is inversely proportional to the amount of free antigen or antibody present in the sample.

Noncompetitive assays can be, for example, sandwich assays, in which the sample analyte (target antibody) is bound between two analyte-specific binding reagents. One of the binding agents is used as a capture agent and is bound to a solid surface. The other binding agent is labeled and is used to measure or detect the resultant antigen/antibody complex by e.g., visual or instrument means. A number of combinations of capture agent and labeled binding agent can be used. For instance, antigens derived from the T. vaginalis can be used as the capture agent and labeled anti-human antibodies specific for the constant region of human antibodies can be used as the labeled binding agent to detect antibodies in a sample that bind the T. vaginalis antigen. Goat, sheep and other non-human antibodies specific for human immunoglobulin constant regions are well known in the art. Alternatively, the anti-human antibodies can be the capture agent and the antigen can be labeled. Other proteins capable of specifically binding human immunoglobulin constant regions, such as protein A, protein L or protein G can also be used as the capture agent or labeled binding agent. These proteins are normal constituents of the cell walls of streptococcal bacteria. They exhibit a strong non-immunogenic reactivity with immunoglobulin constant regions from a variety of species. (See, e.g., Kronval, et al., J. Immunol., 111:1401-1406 (1973); Akerstrom, et al., J. Immunol., 135:2589-2542 (1985).)

The non-competitive assays need not be sandwich assays. For instance, the antibodies or antigens in the sample can be bound directly to the solid surface. The presence of antibodies or antigens in the sample can then be detected using labeled antigen or antibody, respectively.

In some embodiments, antibodies and/or T. vaginalis protein or epitopes of proteins either singly or in combination of aldolase, GAPDH, α-enolase and/or α-actinin proteins, can be conjugated or otherwise linked or connected (e.g., covalently or non-covalently) to a solid support (e.g., bead, plate, slide, dish, membrane or well) in accordance with known techniques. Further, a plasmid construct encoding a recombinant protein that contains the epitopes of aldolase, GAPDH, α-enolase and/or α-actinin proteins detected by human antibodies following infection by and exposure to T. vaginalis can be used. This protein comprised by a series of the epitope sequences is referred to as a SOE, rSOE, or SOP with each “pearl” representing an individual epitope, and the epitope can be separated by amino acid repeats, such as glycine (-GG-) or lysine (-KK-). Antibodies can also be conjugated or otherwise linked or connected to detectable groups such as radiolabels (e.g., ³⁵S, ¹²⁵I, ³²P, ¹³H, ¹⁴C, ¹³¹I), enzyme labels (e.g., horseradish peroxidase, alkaline phosphatase), gold beads, chemiluminescence labels, ligands (e.g., biotin) and/or fluorescence labels (e.g., fluorescein isothiocyanate) in accordance with known techniques.

A variety of organic and inorganic polymers, both natural and synthetic can be used as the material for the solid surface. Non-limiting examples of polymers include polyethylene, polypropylene, poly(4-methylbutene), polystyrene, polymethacrylate, poly(ethylene terephthalate), rayon, nylon, poly(vinyl butyrate), polyvinylidene difluoride (PVDF), silicones, polyformaldehyde, cellulose, cellulose acetate, nitrocellulose, and the like. Other materials that can be used include, but are not limited to, include paper, glass, ceramic, metal, metalloids, semiconductive materials, cements and the like. In addition, substances that form gels, such as proteins (e.g., gelatins), lipopolysaccharides, silicates, agarose and polyacrylamides can be used. Polymers that form several aqueous phases, such as dextrans, polyalkylene glycols or surfactants, such as phospholipids, long chain (12-24 carbon atoms) alkyl ammonium salts and the like are also suitable. Where the solid surface is porous, various pore sizes can be employed depending upon the nature of the system.

A variety of immunoassay systems can be used, including but not limited to, radio-immunoassays (RIA), enzyme-linked immunosorbent assays (ELISA) assays, enzyme immunoassays (EIA), “sandwich” assays, gel diffusion precipitation reactions, immunodiffusion assays, agglutination assays, immunofluorescence assays, fluorescence activated cell sorting (FACS) assays, immunohistochemical assays, protein A immunoassays, protein G immunoassays, protein L immunoassays, biotin/avidin assays, biotin/streptavidin assays, immunoelectrophoresis assays, precipitation/flocculation reactions, immunoblots (Western blot; dot/slot blot); immunodiffusion assays; liposome immunoassay, chemiluminescence assays, library screens, expression arrays, etc., immunoprecipitation, competitive binding assays and immunohistochemical staining. These and other assays are described, among other places, in Hampton et al. (Serological Methods, a Laboratory Manual, APS Press, St Paul, Minn. (1990)) and Maddox, et al. (J. Exp. Med. 158:1211-1216 (1993)).

The methods of this invention can also be carried out using a variety of solid phase systems, such as described in U.S. Pat. No. 5,879,881, as well as in a dry strip lateral flow system, such as described, for example, in U.S. Patent Publication No. 20030073147, the entire contents of each of which are incorporated by reference herein.

A subject of this invention is any animal that can be infected by Trichomonas vaginalis. In certain embodiments, the subject is human.

In addition, a nucleic acid (DNA) having the nucleotide sequence or a substantially similar nucleotide sequence of the gene encoding the T. vaginalis protein of this invention can be used as a probe in a nucleic acid hybridization assay for the detection of a T. vaginalis protein in various tissues or body fluids of a subject of this invention. Further, DNA encoding the sequence of the epitopes, 15-mer epitopes, and/or SOEs of this invention detected by human serum following infection by and exposure to T. vaginalis can be used as a probe in a nucleic acid hybridization assay for the detection of a T. vaginalis protein in various tissues or body fluids of a subject of this invention. The probe can be used in any type of nucleic acid hybridization assay including Southern blots (Southern, 1975, J. Mol. Biol. 98:508), Northern blots (Thomas et al., 1980, Proc. Natl Acad. Sci. U.S.A. 77:5201-05), colony blots (Grunstein, et al., 1975, Proc. Natl Acad. Sci. U.S.A. 72:3961-65), slot blots, dot blots, etc. Stringency of hybridization can be varied depending on the requirements of the assay according to methods well known in the art. Assays for detecting nucleic acid encoding a T. vaginalis protein in a cell, or the amount thereof, typically involve, first contacting the cells or extracts of the cells containing nucleic acids therefrom with an oligonucleotide probe that specifically binds to nucleic acid encoding a T. vaginalis protein or peptide as described herein (typically under conditions that permit access of the oligonucleotide to intracellular material), and then detecting the presence or absence of binding of the oligonucleotide probe thereto. Any suitable assay format can be employed (see, e.g., U.S. Pat. Nos. 4,358,535; 4,302,204; 4,994,373; 4,486,539; 4,563,419; and 4,868,104, the disclosures of each of which are incorporated herein by reference in their entireties).

The antibodies of this invention can be used in in vitro, in vivo and/or in in situ assays to detect a T. vaginalis protein or peptide of this invention.

Also as used herein, the terms peptide and polypeptide are used to describe a chain of amino acids, which correspond to those encoded by a nucleic acid (DNA). A peptide usually describes a chain of amino acids of from two to about 30 amino acids and polypeptide usually describes a chain of amino acids having more than about 30 amino acids. It is understood, however, that 30 is an arbitrary number with regard to distinguishing peptides and polypeptides and the terms may be used interchangeably for a chain of amino acids around 30. The peptides and polypeptides of the present invention are obtained by isolation and purification of the peptides and polypeptides from cells where they are produced naturally or by expression of a recombinant and/or synthetic nucleic acid encoding the peptide or polypeptide. The peptides and polypeptides of this invention can be obtained by chemical synthesis, by proteolytic cleavage of a polypeptide and/or by synthesis from nucleic acid encoding the peptide or polypeptide. The term polypeptide can refer to a linear chain of amino acids or it can refer to a chain of amino acids, which have been processed and folded into a functional protein. The term polypeptide can refer also the sequence of the epitopes. Using T. vaginalis as an example, the selected epitopes from the proteins of aldolase, GAPDH, α-enolase, and/or α-actinin are arranged so that each epitope is separated by amino acid repeats, such as glycine or lysine, in the form of an SOE, rSOE, or SOP.

It is also understood that the peptides and polypeptides of this invention may also contain conservative substitutions where a naturally occurring amino acid is replaced by one having similar properties and which does not alter the function of the peptide or polypeptide. Such conservative substitutions are well known in the art. Thus, it is understood that, where desired, modifications and changes may be made in the nucleic acid and/or amino acid sequence of the peptides and polypeptides of the present invention and still obtain a peptide or polypeptide having like or otherwise desirable characteristics. Such changes may occur in natural isolates or may be synthetically introduced using site-specific mutagenesis, the procedures for which, such as mismatch polymerase chain reaction (PCR), are well known in the art. One of skill in the art will also understand that polypeptides and nucleic acids that contain modified amino acids and nucleotides, respectively (e.g., to increase the half-life and/or the therapeutic efficacy of the molecule), can be used in the methods of the invention.

“Nucleic acid” as used herein refers to single- or double-stranded molecules which may be DNA, comprised of the nucleotide bases A, T, C and G, or RNA, comprised of the bases A, U (substitutes for T), C, and G. The nucleic acid may represent a coding strand or its complement. Nucleic acids may be identical in sequence to a sequence that is naturally occurring or may include alternative codons that encode the same amino acid as that which is found in the naturally occurring sequence. Furthermore, nucleic acids may include codons that represent conservative substitutions of amino acids as are well known in the art. The nucleic acids of this invention can also comprise any nucleotide analogs and/or derivatives as are well known in the art.

As used herein, the term “isolated nucleic acid” means a nucleic acid separated or substantially free from at least some of the other components of the naturally-occurring organism, for example, the cell structural components commonly found associated with nucleic acids in a cellular environment and/or other nucleic acids. The isolation of nucleic acids can therefore be accomplished by well-known techniques such as cell lysis followed by phenol plus chloroform extraction, followed by ethanol precipitation of the nucleic acids. The nucleic acids of this invention can be isolated from cells according to methods well known in the art for isolating nucleic acids. Alternatively, the nucleic acids of the present invention can be synthesized according to standard protocols well described in the literature for synthesizing nucleic acids. Modifications to the nucleic acids of the invention are also contemplated, provided that the essential structure and function of the peptide or polypeptide encoded by the nucleic acid are maintained.

The nucleic acid encoding the peptide or polypeptide of this invention can be part of a recombinant nucleic acid construct comprising any combination of restriction sites and/or functional elements as are well known in the art that facilitate molecular cloning and other recombinant DNA manipulations. Thus, the present invention further provides a recombinant nucleic acid construct comprising a nucleic acid encoding a peptide and/or polypeptide of this invention. The protein products of combinations of genetic sequences into a recombinant nucleic acid are sometimes referred to as chimeric proteins, polypeptides and/or peptides, and the SOEs of the invention can be called such.

The present invention further provides a vector comprising a nucleic acid encoding a peptide and/or polypeptide of this invention. The vector can be an expression vector which contains all of the genetic components required for expression of the nucleic acid in cells into which the vector has been introduced, as are well known in the art. The expression vector can be a commercial expression vector or it can be constructed in the laboratory according to standard molecular biology protocols. The expression vector can comprise, for example, viral nucleic acid including, but not limited to, vaccinia virus, adenovirus, retrovirus, alphavirus and/or adeno-associated virus nucleic acid. The nucleic acid or vector of this invention can also be in a liposome or a delivery vehicle, which can be taken up by a cell via receptor-mediated or other type of endocytosis.

The nucleic acid of this invention can be in a cell, which can be a cell expressing the nucleic acid whereby a peptide and/or polypeptide of this invention is produced in the cell. In addition, the vector of this invention can be in a cell, which can be a cell expressing the nucleic acid of the vector whereby a peptide and/or polypeptide of this invention is produced in the cell. It is also contemplated that the nucleic acids and/or vectors of this invention can be present in a host (e.g., a bacterial cell, a cell line, a transgenic animal, etc.) that can express the peptides and/or polypeptides of the present invention.

In some embodiments, for recombinant production of the chimeric proteins, polypeptides and/or peptides of this invention in prokaryotes, there are numerous Escherichia coli (E. coli) expression vectors known to one of ordinary skill in the art useful for the expression of nucleic acid encoding proteins or peptides of this invention. Other microbial hosts suitable for use include bacilli, such as Bacillus subtilis, and other enterobacteria, such as Salmonella, Shigella, and Serratia, as well as various Pseudomonas species. These prokaryotic hosts can support expression vectors that will typically contain sequences compatible with the host cell (e.g., an origin of replication). In addition, any number of a variety of well-known promoters will be present, such as the lactose promoter system, a tryptophan (Trp) promoter system, a beta-lactamase promoter system, or a promoter system from phage lambda. The promoters will typically control expression, optionally with an operator sequence and have ribosome binding site sequences for example, for initiating and completing transcription and translation. If necessary, an amino terminal methionine can be provided by insertion of a Met codon 5′ and in-frame with the coding sequence of the protein. Also, the carboxy-terminal extension of the protein can be removed using standard oligonucleotide mutagenesis procedures.

Additionally, yeast expression systems and baculovirus systems, which are well known in the art, can be used to produce the chimeric peptides and polypeptides of this invention.

The vectors of this invention can be transferred into a cell by well-known methods, which vary depending on the type of cell host. For example, calcium chloride transfection is commonly utilized for prokaryotic cells, whereas calcium phosphate treatment, lipofection or electroporation can be used for other cell hosts.

The present invention further provides a kit for detection of microorganism-specific proteins. In the case of T. vaginalis, at least one antibody is selected from the group consisting of aldolase, GAPDH, α-enolase and/or α-actinin antibodies, as disclosed in the sequence listings and tables herein. Such a kit can comprise one or more proteins or antibodies of the invention, along with suitable buffers, wash solutions, dilution buffers, secondary antibodies, and detection reagents for the detection of antigen/antibody complex formation under various conditions. In another embodiment, a kit of this invention can comprise at least one amino acid sequence selected from the group consisting of SOE, polypeptide, a peptide, and antigenic fragment comprising the amino acid sequence (epitope) detected by the monoclonal antibody and/or a fusion protein or peptide comprising an individually or in combination the epitopes of interest, along with suitable buffers, wash solutions, dilution buffers, secondary antibodies, detection reagents, etc. for the detection of antigen/antibody complex formation under various conditions.

EXAMPLES OF THE INVENTION

The present invention is more particularly described in the Examples set forth below, which are not intended to be limiting of the embodiments of this invention.

Example 1. Monoclonal Antibodies (MAbs) that Specifically Bind a Trichomonas Vaginalis Fructose-1,6-Biphosphate Aldolase (Aldolase), Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH), and/or α-Enolase Proteins

Detecting a T. vaginalis protein selected from aldolase, GAPDH, α-enolase and/or α-actinin proteins, in a sample, includes contacting a sample with an antibody that specifically binds a T. vaginalis protein or epitopes of proteins either singly or in combination selected from the group of aldolase, GAPDH, α-enolase and α-actinin proteins, under conditions whereby an antigen/antibody complex can form, and detecting formation of an antigen/antibody complex, thereby detecting the protein in the sample. The method may be performed using an immunoassay, such as a dot blot, ELISA, or other high-throughput immunoassay, with ELISA being the preferred immunoassay.

In particular embodiments of this invention, the antibody employed in the methods of this invention is an antibody that specifically binds a T. vaginalis protein or epitopes of the proteins either singly or in combination selected from aldolase, GAPDH, α-enolase and/or α-actinin proteins. A non-limiting example of an antibody that specifically binds the known amino sequence of the epitope of a T. vaginalis protein selected from aldolase, GAPDH, α-enolase and/or α-actinin proteins is monoclonal antibody ALDwsu1 (aldolase), ALDwsu2 (aldolase), GAPwsu2 (GAPDH), GAPwsu3 (GAPDH), ENOwsu2 (α-enolase), ENOwsu3 (α-enolase), ENOwsu4 (α-enolase), ENOwsu6 (α-enolase) and HA423 (α-actinin).

A library of new monoclonal antibodies (MAbs) was generated toward the T. vaginalis proteins aldolase, glyceraldehyde-3-phosphate-dehydrogenase, and α-enolase proteins. The newly-generated MAbs are all IgG₁ isotype. MAbs B44, B43, and HA423 are included for comparative purposes and were generated at the University of Texas Health Science Center at San Antonio but the epitope amino acid sequences were unknown until now. All of the newly-generated MAbs readily detect the surface of trichomonads as evidenced by whole cell-enzyme-linked immunosorbent assay (WC-ELISA) and fluorescence of non-permeabilized organisms. The respective proteins are detected by immunoblot after SDS-PAGE blotting the proteins onto nitrocellulose after probing with individual MAbs. The amino acid sequences detected by the respective MAbs (epitopes) are provided, and it is noteworthy that the epitopes detected by the MAbs generated at WSU are different from that B44 and B43 MAbs.

In certain embodiments, an antibody of this invention is not cross-reactive with human epithelial cell extracts or other protozoan protein extracts (e.g., G. lamblia, E. histolytica, A. castellanii, L. major), fungi (Candida and pneumocystis), and bacteria (oral and vaginal bacterial flora). In yet other embodiments, an antibody of this invention does not bind or react with T. vaginalis adhesin proteins.

TABLE 1 New MAbs generated and reactive with aldolase (ALD), GAPDH (GAP), α-enolase (ENO), and α-actinin. amino acid original WSU MAb numbers in epitope  surface size protein name designation¹ protein sequence detection (kDa) SEQ ID NO: 1 ALD ALD12A ALDwsu-1 142-149 RPDYVTVE yes 36.3 SEQ ID NO: 2 ALD ALD64A ALDwsu-2 166-173 KHTYTRPE yes ″ SEQ ID NO: 3 ALD B44 N/A 448-455 ERIQKYTR yes 52 SEQ ID NO: 4 ALD ALD11A ENOwsu-2 364-371 DDLYTTNP yes ″ SEQ ID NO: 5 ALD ALD13B ENOwsu-3  7-14 AIVKECIA yes ″ SEQ ID NO: 6 ALD ALD25 ENOwsu-4 463-470 LKEHDMLA yes ″ SEQ ID NO: 7 ENO ALD55 ENOwsu-6 64-71 YLGRVTLA yes ″ SEQ ID NO: 8 GAP B43 N/A 205-212 RRARAAGM yes 39.2 SEQ ID NO: 9 GAP ALD30A GAPwsu-2 70-77 KSIGGRLG yes ″ SEQ ID NO: 10 GAP ALD32C GAPwsu-3 34-44 YLLKYDTAHRA yes ″ SEQ ID NO: 11 ACT HA423 N/A 649-653 YKVTY yes 106.2 Detection of Fixed Trichomonas vaginalis Protein in Fixed Cell Preparations.

Pap smears were prepared using methanol (MeOH) as a fixative with MeOH in the range of 20% to 80%. Trichomonads are readily fixed by incubation in MeOH prepared in PBS buffer and retain integrity as visualized by darkfield microscopy. Surface-exposed epitopes are readily detected by MAbs as shown in Table 1.

The following ELISA protocol used for pap smear was used to show immunodetection of protein on MeOH-fixed trichomonads immobilized onto wells of microtiter plates.

-   1. Overnight (o/n) cultures of T. vaginalis grown using standard     protocols in medium were washed twice with ice-cold PBS. -   2. Trichomonads were fixed o/n at 4° C. (12 h to 18 h) using 20%     MeOH (different concentrations of MeOH yield similar results) at a     density of 10⁷ per milliliter (ml). -   3. 100 microliters (μl) of different dilutions of parasites in MeOH     fixative were added to individual wells of 96-well microtiter     plates, and plates were placed in 37° C. incubator overnight. -   4. To dried wells was added 1000 of a solution of 1% BSA in PBS-1%     Tween (PBS-T) and incubated at 37° C. for 30 min. -   5. Wells were then washed 3-times (3×) with PBS-T followed by     addition of 1000 of each MAb (primary antibody) to wells. Negative     controls included PBS (absence of primary MAb) and the addition of     MAb L64, which detects a small-sized (17-kDa) cytoplasmic protein.     (NOTE: This MAb of the same isotype (IgG₁) does not detect the     parasite surface showing the integrity of parasites by fixation.)     Wells were incubated for 60 min at 37° C. -   6. After washing 3× with PBS-T, 1000 of a solution of secondary     horseradish peroxidase-conjugated goat anti-mouse IgG antibody was     added to wells followed by incubation at 37° C. for 30 min. -   7. The wells were again washed 3× with PBS-T prior to addition of     100 μl of color development reagent. After 15 min, the microtiter     well plates were read for intensity of optical density at 405 nm     wavelength to measure absorbance values. A higher the absorbance     value at 405 nm indicates strong immunoreactivity by MAb with the     protein antigen on the surface of MeOH-fixed parasites.     Results are shown in FIGS. 1 and 2. Among noteworthy findings are     the following:     -   a) Sensitivity was ≥1 organism per 0 of sample. Wells were         incubated with 100 μl of the parasite suspension ≥10³/ml. At the         lowest density, this is equal to 100 organisms added to each         well.     -   b) All trichomonad isolates are readily detected.     -   c) Parasite preparations made with a poly-bacterial         contamination does not interfere with MAb detection.     -   d) The presence of epithelial cells contaminating trichomonad         preparations does not interfere with MAb detection.     -   e) Newly-generated MAbs give higher signal compared to the HA423         MAb patented to the University of Texas system.     -   f) Protein was detected using the range of MeOH for fixation.     -   g) The signal was enhanced when a cocktail of three MAbs, one         each for aldolase, GAPDH, and α-enolase, was used.

Example 2. Detection of Trichomonas Vaginalis Proteins and Antibodies in Saliva

T. vaginalis is a urogenital, mucosal parasite. Presently, there exists a point-of-care, antigen detection, lateral flow, immunochromagraphic diagnostic that is used for women. This diagnostic is not useful for diagnosis in men. This diagnostic is invasive for women, because it requires obtaining a vaginal swab. Therefore, there is a need for a different, non-invasive diagnostic that will work for both men and women.

Both female and male patients make specific anti-trichomonad surface protein IgG antibody. This antibody is detectable in serum and vaginal washes in women and serum in males. Antibody at one mucosal site makes it possible to detect the antibody at distant mucosal sites. Patients are known to make antibody to the proteins aldolase, GAPDH, α-enolase and α-actinin, making these proteins candidates for detection by saliva. Therefore, a diagnostic based on saliva antibody that detects these proteins or epitopes of the proteins either singly or in combination immobilized on a platform represents a diagnostic that is used for both female and male patients.

The availability of the MAbs to these proteins permits purification of recombinant proteins from cDNA expression libraries or by purification by MAb-affinity column chromatography. Alternatively, the epitopes known to be reactive by sera of both women and men represent targets that can be synthesized and immobilized for detection by saliva. Therefore, the individual or combination of aldolase, GAPDH, and α-enolase proteins or the combination of reactive epitopes of the proteins aldolase, GAPDH, and α-enolase are reagents used in a non-invasive, oral-saliva based diagnostic. Finally, the polypeptide either synthesized or derived from recombinant DNA that possess the sequence of the epitopes in the proteins of aldolase, GAPDH, α-enolase, and/or α-actinin whereby each epitope is separated by such amino acids as glycine or lysine (SOE) is a reagent used in a non-invasive, oral-saliva based diagnostic.

Patient saliva has antibody specific to whole cell T. vaginalis and to trichomonad proteins of aldolase, GAPDH, α-enolase, and/or α-actinin. A whole cell-ELISA was carried out, in which microtiter wells were coated with whole T. vaginalis cells. Saliva of individual T. vaginalis-infected patients and pooled saliva of healthy, uninfected individuals were then tested for reactive IgG using horse radish peroxidase-conjugated anti-human IgG secondary antibody. Each patient shows elevated absorbance values compared to the control pooled saliva of uninfected individuals. This study demonstrates the presence of IgG antibody reactive to whole T. vaginalis proteins. Wells coated with whole cells tested separately using rabbit anti-T. vaginalis serum or with a MAb served as positive controls and were also used for standardization to show similar reactions among wells. Non-reactive serum of men and women and prebleed normal rabbit serum served as negative controls.

In separate experiments, the individual sera of women and men highly reactive with the whole cell-ELISA and with each of the aldolase, GAPDH, α-enolase, and α-actinin proteins above were each reacted with overlapping, synthetically-made dodecapeptides comprising the entire amino acid sequence of the aldolase, GAPDH, α-enolase proteins and α-actinin proteins. The overlapping dodecapeptides were spotted (immobilized) onto a membrane that was then probed individually with 10% dilution of highly WC-ELISA reactive sera of women or men. The sera detected all of the epitopes to which antibody was present. No dodecapeptides were detected by negative control, unreactive sera of women and men. This study demonstrates the existence and immunoreactivity of sera of both women and men to various epitopes and also demonstrated that the women and men sera detected the same epitopes recognized by the MAbs included in Table 1 to the aldolase, GAPDH, α-enolase and α-actinin proteins.

In yet another experiment, the individual sera of women and men highly reactive with T. vaginalis organisms and with each of the aldolase, GAPDH, α-enolase, and α-actinin proteins above were each reacted with synthetic 15-mer peptides possessing the epitopes of the aldolase, GAPDH, α-enolase, and α-actinin proteins either singly or in combination were immobilized onto a membrane that was then probed individually with 10% dilution of highly WC-ELISA reactive sera of women or men. The sera detected all of the epitopes to epitopes singly and in combination. No peptides singly or in combination were detected by negative control, unreactive sera of women and men. This study demonstrates the existence and immunoreactivity of sera of both women and men to various epitopes and also demonstrated that the women and men sera detected the same epitopes recognized by the MAbs included in Table 1 to the aldolase, GAPDH, α-enolase and α-actinin proteins.

In yet another experiment, the individual sera of women and men highly reactive with T. vaginalis organisms and with each of the aldolase, GAPDH, α-enolase, and α-actinin proteins above were each reacted with a recombinant polypeptide possessing the epitopes of the aldolase, GAPDH, α-enolase, and α-actinin proteins (SOE) immobilized onto a membrane that was then probed individually with 10% dilution of highly WC-ELISA reactive sera of women or men. The sera detected all of the epitopes this recombinant polypeptide possessing the epitopes of the aldolase, GAPDH, α-enolase, and α-actinin proteins. No peptides singly or in combination were detected by negative control, unreactive sera of women and men. This study demonstrates the existence and immunoreactivity of sera of both women and men to various epitopes and also demonstrated that the women and men sera detected the same epitopes recognized by the MAbs included in Table 1 to the aldolase, GAPDH, α-enolase and α-actinin proteins.

No crossreactivity of saliva antibody between T. vaginalis and the opportunistic oral T. tenax. Saliva of humans uninfected with T. vaginalis has no detectable antibody using any of the ELISA assays mentioned above. Thus, the existence of immunocrossreactive antibodies in saliva of patients to T. tenax, the oral trichomonad will be non-existent. T. tenax organisms are not readily apparent in the oral cavity and are not detectable in individuals even if there is severe periodontitis.

Demonstration of Specific Anti-T. vaginalis Antibody in Saliva of Patients.

Standard ELISA can demonstrate the existence of saliva antibody in all patients. The assays can be optimized to minimize any crossreactive antibody to T. tenax and to monitor the level of saliva antibody among the patients, although, as just mentioned above, there is no evidence of salivary antibody crossreactivity with T. tenax. Three different assays provide a basis by which to determine the level of antibody to trichomonad proteins in saliva. ELISA protocols that bind non-specific sites on the coated wells with irrelevant proteins, such as BSA and/or or skim milk, can be employed. The first ELISA has whole intact trichomonads coated onto 96-well microtiter plates as antigen for saliva antibody detection, and this whole cell-ELISA employs standard conditions. For this whole cell ELISA, MeOH-fixed trichomonads can be used, or, alternatively, PBS-washed organisms can be added to wells and allowed to dry o/n. Then ethanol is added to the dried wells, and wells allowed to dry and fix the trichomonads onto the wells. The second ELISA has purified IgG of high-titered rabbit antisera to total trichomonad proteins coated onto microtiter wells. Then, trichomonad protein antigens from a detergent extract of T. vaginalis will bind to the IgG-coated wells after incubation. The bound trichomonad proteins provide antigen detectable by saliva antibody. Similarly, the third assay has a cocktail of MAbs to aldolase, GAPDH, α-enolase and α-actinin-coated onto microtiter wells. These MAbs-coated wells bind protein antigen from the trichomonal extract. These parasite proteins bound to MAbs will now serve as antigen for saliva antibody. The second and third sandwich-ELISAs take advantage of the knowledge that women and men make serum antibody to various epitopes of each protein (Table 1). It is expected that saliva antibody, like serum antibody, is directed to epitopes different from those of rabbit antiserum and that we have now shown are detected by serum antibody of women and men infected and exposed to T. vaginalis.

After treatment of freshly prepared ELISA plates with skim milk to decrease non-specific interactions, select samples of saliva from patients and from uninfected control individuals can be diluted in PBS without or with a T. tenax detergent extract prior to addition of standard 100 μl volumes to microtiter wells. PBS without T. tenax extract provides duplicates of the same saliva. Initial data shows that saliva does not have any antibody to T. tenax, and data suggests that any concern of crossreactivity is nonexistent. Experiments indicate that a 60 min to 120 min incubation at 37° C. is optimal. After washing, horseradish peroxidase-conjugated secondary goat anti-human IgG, anti-IgA, or Ig (IgG+IgA+IgM) Ab is added, followed by color development with substrate. In these assays, purified trichomonad protein called P230 that is a prominent immunogen eliciting a vaginal IgG antibody response will serve as a positive control for saliva IgG antibody.

Saliva antibody from women infected with T. vaginalis and after treatment is tested. Saliva can be obtained on at least two occasions post-treatment to assess the nature of the antibody response following removal of trichomonads from the urogenital tract through drug treatment. Saliva from male partners of infected women can also be examined to confirm the validity of this diagnostic for both infected partners.

Example 3. Trichomonas vaginalis Proteins Detected in Urine by MAbs

The numerous proteins that are increased in expression during infection, found in secretions of patients, and are readily secreted by trichomonads have been identified and include aldolase, GAPDH, α-enolase and α-actinin. Both women and men patients infected with T. vaginalis have trichomonads in urine. This means that many proteins and/or intact organisms may be detected in urine samples for both women and men. Among the many secreted proteins found in large amounts are those to which the new MAbs have been generated, and these proteins are aldolase, GAPDH, and/or α-enolase. These proteins are readily detected by immunoblots with the MAbs to aldolase, GAPDH, α-enolase and/or α-actinin. Therefore, these proteins in soluble form in urine can be immobilized through filtration and can then be detected by the MAbs. Therefore, the MAbs are reagents that are critical for this urine-based diagnostic. Although the present invention has been described with reference to specific details of certain embodiments thereof, it is not intended that such details should be regarded as limitations upon the scope of the invention except as and to the extent that they are included in the accompanying claims. Throughout this application, various patents, patent publications and non-patent publications are referenced. The disclosures of these patents, patent publications, and non-patent publications in their entireties are incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains.

Overview of Examples 4 Through 7: Identification of Diagnostic Immunogenic Epitopes of Aldolase, GAPDH, α-Enolase, and α-Actinin that are Reactive with Sera of Female and Male Patients and Monoclonal Antibodies (MAbs) and are Unique to Trichomonas vaginalis

We have identified epitopes of the T. vaginalis proteins aldolase, GAPDH, α-enolase, and α-actinin with little or no identity to other sexually transmitted microorganisms [Treponema pallidum (syphilis), Chlamydia trachomatis (chlamydia), Neisseria gonorrhoeae (gonorrhea), and Candida albicans (yeast)], normal flora bacteria (E. coli), yeast (Saccharoinyces cerevisiae), and humans (Homo sapiens) and are, therefore, unique targets to diagnose infection and exposure to T. vaginalis. These peptide epitopes have significance for diagnosis of infection with T. vaginalis. The experimental approach likewise identified epitopes in the trichomonad GAPDH and α-enolase proteins with significant identity to peptide epitopes in the human proteins to which individuals infected with T. vaginalis make antibody. Such antibody during a T. vaginalis infection may have consequences for autoimmunity. The GAPDH peptide epitopes were found to have high sequence identity to the GAPDH protein of Tritrichomonas suis parasite of porcine, which is a synonym for Tritrichomonas foetus-bovine, the causative agent of fetal wastage in cattle, Tritrichomonas foetus-cat, causative agent for chronic large-bowel diarrhea, and Tritrichomonas mobilensis, enteric protozoan of squirrel monkeys (Lun, Z.-R., et al., Trends in Parasitol., 21:122-125, 2005; Reinmann, K., et al., Veterinary Parasitol., published ahead of print, doi: 10.1016/j.vetpar.2011.09.032.). Therefore, these epitope characterization experiments have identified diagnostic epitopes of the important pathogenic porcine, cattle, cat, and squirrel monkey trichomonads (Tritrichomonas suis, T. foetus-bovine, T. foetus-cat, and T. mobilensis).

Overlapping dodecapeptides of each of the aldolase, GAPDH, α-enolase and α-actinin proteins were examined for immunoreactivity with the sera of women and men patients and MAbs. The overlapping dodecapeptides for each of the proteins were immobilized in succeeding spots on a template that permitted detection by antibodies. This procedure is standard for identification of epitopes immunogenic during infection or that react with serum antibody and MAbs. This approach permits analysis of the antibody responses that are similar and distinct between the sera of women and men patients in addition to localizing the epitopes detected by MAbs. Further, it is possible to perform comparative analysis of the amino acid sequences of similar functional proteins of humans (Homo sapiens), of other sexually transmitted bacterial pathogens (Neisseria gonorrhoeae, Treponema pallidum subsp. pallidum strain Nichols, and Chlamydia trachomatis), of yeast (Saccharomyces cerevisiae and Candida albicans), and of other human bacterial pathogens (Streptococcus pyogenes, Streptococcus pneumoniae, and Staphylococcus aureus). Alignment of the amino acid sequences reveals whether the peptide sequences are unique to Trichomonas vaginalis, are identical and common to other Trichomonas sp. (T. suis and synonyms T. foetus-bovine, T. foetus-cat, and T. mobilensis), and share high or identical sequence identity with humans (H. sapiens) that may have significance for autoimmune reactions.

Accompanying each of the following experiments are tables showing the diagnostic immunogenic sequences reactive with female and male sera and MAbs that are unique to T. vaginalis. Other tables illustrate the extent of sequence identity between the T. vaginalis amino acid sequences with those of other bacteria, yeast, and human. These alignments were obtained from BLAST amino acid sequence alignments of proteins. Spot numbers on the overlapping peptides and the numbers of amino acids in the T. vaginalis peptide epitopes reactive with female (F) and male (M) sera and MAbs and that are unique to T. vaginalis are provided under the column labeled “unique Tv epitope for diagnosis” and given a positive (+) sign. T. vaginalis peptide epitopes with high sequence identity to Tritrichomonas suis (synonym with T. foetus-bovine, T. foetus-cat, and T. mobilensis) protein epitope sequences are also disclosed. These peptides are reactive with female or male sera or both, and illustrate their utility also for diagnosis of porcine, cattle, cat, and squirrel monkey trichomonads. The peptides of the proteins α-enolase and GAPDH with high sequence identity to human protein epitopes and with possible autoimmune crossreactivity are listed, and the T. vaginalis (Tv) peptide sequences are aligned with the human sequences (Hu).

Example 4. Identification of Diagnostic Immunogenic Epitopes of Aldolase Unique to T. vaginalis

TABLE 2 Identification of diagnostic immunogenic epitopes of fructose-1,6-biphosphate aldolase protein that are unique to T. vaginalis (Tv). no. amino female male patient unique acid patient sera sera Mab To sequence epitope sequence reactivity reactivity reactivity Tv SEQ ID NO: 12 40-47 AIITASVK F1 SEQ ID NO: 13 58-65 AGARKYAN M1 SEQ ID NO: 14 61-71 RKYANQTMLRY F2 SEQ ID NO: 15  91-101 PIVLHLDHGDS F3 SEQ ID NO: 1 142-149 RPDYVTVE ALD12A SEQ ID NO: 2 166-173 KHYTYTRPE ALD64A + SEQ ID NO: 16 169-179 YTRPEEVQDFV F4 SEQ ID NO: 17 193-203 TSHGAYKFPPG F5 SEQ ID NO: 18 231-241 SIPQEYVEMVN F6 SEQ ID NO: 19 277-287 RMVMTGTIRRL M2 SEQ ID NO: 20 298-305 RQYLGEAR F7 M3 SEQ ID NO: 21 304-311 ARTKLTEM F8 + The range of percent identity of these peptide epitopes with selected pathogens and humans is illustrated in the sequence alignment data of FIGS. 3A, 3B, and 3C. Abbreviations F and M refer to female and male patient sera reactive with corresponding epitopes. The plus (+) sign refers to the epitope sequences that are unique to T. vaginalis, as evidenced by absence of sequence identity shown in FIGS. 3A, 3B, and 3C. Sequence Alignment of the T. vaginalis Fructose-1,6-Bisphosphate Aldolase (ALD) Protein with ALD Proteins of Other Representative Organisms and H. sapiens.

FIGS. 3A, 3B, and 3C shows the amino acid sequence comparison of T. vaginalis (Tv, SEQ ID NO:147) ALD with the homolog proteins from Treponema pallidum (Tp, SEQ ID NO:148), Neisseria gonorrhoeae (Ng, SEQ ID NO:149), Streptococcus pyogenes (Spy, SEQ ID NO:150), Streptococcus pneumoniae (Spn, SEQ ID NO:151), Staphylococcus aureus (Sa, SEQ ID NO:152), Escherichia coli. Candida albicans, Saccharomyces cerevisiae, and Homo sapiens. The boxed amino acids contained in the T. vaginalis sequence are the epitopes presented in Table 2. The order from top to bottom of the sequences is based on from highest to lowest percent identity compared to T. vaginalis ALD sequence. All microorganisms represented are pathogens, and 15-mer epitopes and/or SOEs derived from the ALD or other proteins may be used to practice the invention.

TABLE 3 Aldolase percent epitope sequence identity comparisons with bacterial, yeast, and human sequences from alignment shown in FIGS. 3A, 3B, and 3C. ALD12A and ALD64A are MAbs. Epitope F7 Organism F1 M1 F2 F3 ALD12A ALD64A F4 F5 F6 M2 M3 F8 T. vaginalis 100 100 100 100 100 100 100 100 100 100 100 100 T. pallidum 62.5 87 72.7 100 87 50 72.7 63.6 54.5 54.5 75 37.5 N. gonorrhoea 37.5 87.5 54.5 63.6 37.5 0 28.57 72.7 45.4 45.4 50 0 S. pyogenes 37.5 44.4 16.7 54.5 37.5 0 14.3 27.3 0 9.1 25 0 S. pneumoniae 37.5 44.4 25 54.5 25.00 0 14.29 27.3 0 9.1 25 0 S. aureus 50 33.3 8.3 63.6 37.5 25 45.4 45.4 0 9.1 75 37.5 E. coli 25 33.3 16.7 63.6 25 25 41.7 45.4 0 9.1 25 12.5 C. albicans 25 33.3 16.7 54.5 12.5 50 35.7 36.4 0 18.2 25 0 S. cerevisiae 25 33.3 16.7 54.5 12.5 50 35.7 27.3 0 18.2 25 0 Homo sapiens 0 12.5 9.1 27.3 0 0 0 9 0 9.1 12.5 0 Hydrophobicity and Antigenicity Profiles of the ALD, ENO, and GAP Sequences.

FIG. 4 presents analyses of hydrophobicity and antigenicity alignments in reference to epitopes along the protein. Of interest is that with few exceptions the epitopes represent hydrophilic regions contained within the protein, perhaps consistent with presentation of amino acids for antibody synthesis and recognition.

Based on the features of the epitopes, 7 epitopes for ALD, 8 for ENO, and 6 for GAP were selected for synthesis of 15-mer peptides encoding in an SOE. The individual amino acid sequence encoding the epitope is bold and underlined.

Example 5. Identification of Diagnostic Immunogenic Epitopes of α-Enolase Unique to Trichomonas vaginalis

TABLE 4 Identification of diagnostic immunogenic epitopes of α-enolase protein unique to T. vaginalis (Tv). Epitope amino acid sequences unique to the T. vaginalis protein are based on percent identity shown in Table 5. SEQ no. female male patient ID  amino acid patient sera sera MAb unique NO: sequence epitope sequence reactivity reactivity reactivity to Tv 22  6-14 AIVKECIA ALD13A + 23 64-71 YLGRVTLA F1 ALD55 + 24 70-77 LAARSSAP M1 + 25  94-101 DKARYGGK F2 M2 26 139-146 TVLKKNIG F3 M3 + 27 184-194 VPKKFKLPSPF F4 M4 + 28 238-246 GGLLVKKY F5 + 29 245-252 KYGLSAKN M7 + 30 298-305 FYDEEKKL M8 + 31 328-338 KKHPAIVSIED F6 32 343-362 ENWTKLNARLG F7 33 364-371 DDLYTTNP ALD11A 34 448-455 ERIQKYTR F9  M11 B44 35 463-471 LKEHDMLA ALD25 +

TABLE 5 The extent of sequence identity of the T. vaginalis α-enolase with the protein sequences of bacteria, yeasts, and human. The epitopes are indicated by F1 through F9, M1 through M7, and the MAbs ALD13A/B, ALD55, ALD11A, and ALD25 are as listed in the Table. Epitope F9 F1 F2 F3 F4 F6 M7 Organism ALD13A ALD55 M1 M2 M3 M4 F5 M5 M6 F7 F8 ALD11A B44 ALD25 T. vaginalis 100 100 100 100 100 100 100 100 100 100 100 100 100 100 T. pallidum 0.00 0.00 25 71.4 37.5 27.3 37.5 0 25 63.6 27.3 50 37.5 5.5 N. gonorrhoeae 0 0 25 71.4 50 27.3 25 12.5 25 54.5 45.4 75 37 10.5 C. trachomatis 0 0 12.5 57.1 37.5 27.3 12.5 0 37.5 54.5 45.4 62.5 75 0 S. pyogenes 0 0 25 71.4 37.5 27.3 12.5 12.5 37.5 54.5 45.4 50 50 10.5 S. pneumoniae 0 0 25 85.7 37.5 27.3 12.5 12.5 37.5 54.5 45.4 50 50 10.5 S. aureus 0 0 25 71.4 37.5 27.3 25 12.5 25 54.5 36.4 62.5 50 10.5 E. coli 0 0 25 57.1 37.5 36.4 25 25 25 72.7 18.3 62.5 37.5 10 C. albicans 0 12.5 50 42.8 37.5 54.5 50 75 37.5 63.6 27.3 75 37.5 6.3 S. cerevisiae 0 0 37.5 42.8 37.5 36.4 37.5 62.5 25 73.7 27.3 75 37.5 6.3 Homo sapiens 0 12.5 37.5 71.4 37.5 27.3 37.5 62.5 37.5 54.5 36.4 75 50 6.3 Abbreviations: F, female antibody reacting with epitope; M, male antibody reacting with epitope; ALD refers to MAbs.

TABLE 6 Identification of epitopes of Trichomonas vaginalis (Tv) α-enolase reactive with human sera.¹ % pooled identity spots female reactive with number on amino acid epitope patient male MAb unique to human membrane sequence sequence sera sera reactions Tv sequence SEQ ID NO: 22 2, 3 6-14 AIVKECIA ALD13A + SEQ ID NO: 23 21-23 64-71 YLGRVTLA F1 ALD55 + SEQ ID NO: 24 23-25 70-77 LAARSSAP M1 + SEQ ID NO: 25 31-33  94-101 DKARYGGK F2 M2 71% SEQ ID NO: 26 46-47 139-146 TVLKKNIG F3 M3 + SEQ ID NO: 27 62 184-194 VPKKFKLPSPF F4 M4 + SEQ ID NO: 135 67 199-209 NGGKHAGGNLK M5 SEQ ID NO: 136 76 226-236 OLRMVAEVYQK M6 SEQ ID NO: 28 79-81 238-246 GGLLVKKY F5 + SEQ ID NO: 29 81-82 245-252 KYGLSAKN M7 62.5%   SEQ ID NO: 30  99-100 298-305 FYDEEKKL M8 + SEQ ID NO: 31 110  328-338 KKHPAIVSIED F6 + SEQ ID NO: 32 115-118 343-362 ENWTKLNARLG F7 + SEQ ID NO: 137 117-118 352-359 NARLGQRV M9 SEQ ID NO: 33 121-123 364-371 DDLYTTNP ALD11A 75% SEQ ID NO: 138 123-124 370-377 NPITIKKG F8  M10 SEQ ID NO: 34 149-151 448-455 ERIQKYTR F9  M11 B44 + SEQ ID NO: 35 154-155 463-471 LKEHDMLA ALD25 +

Example 6. Identification of Diagnostic Immunogenic Epitopes of GAPDH Unique to Trichomonas vaginalis, and Diagnostic Epitopes Identical to or with High Sequence Identity to Tritrichomonas suis (Synonym with T. foetus Bovine, T. foetus Cat, and T. mobilensis)

TABLE 7 Identification of diagnostic immunogenic epitopes of GAPDH protein unique to T. vaginalis. male no. amino acid female patient patient sera MAb unique sequence epitope sequence sera reactivity reactivity reactivity to Tv SEQ ID NO: 36 13-17 LYPKD M1 + SEQ ID NO: 37 34-44 YLLKYDTAHRA F1 ALD32C + SEQ ID NO: 38 58-68 FTVGEGADKWV M2 + SEQ ID NO: 39 70-77 KSIGGRLG F2 ALD30A + SEQ ID NO: 40  94-101 STGIFRTK F3 + SEQ ID NO: 41 106-113 AEGKIKKD F4 + SEQ ID NO: 42 118-125 HLVSGAKK F5 M4 SEQ ID NO: 43 157-161 SNASC M5 SEQ ID NO: 44 175-182 NAFGIRNG F6 + SEQ ID NO: 45 205-212 RRARAAGM F7 B43 SEQ ID NO: 46 217-224 TSTGAAIA F8 SEQ ID NO: 47 229-233 CHGLP M6 SEQ ID NO: 48 250-260 SLVDLTVNVNA F9 SEQ ID NO: 49 292-299 VSSDIIGC M7 SEQ ID NO: 50 298-305 GCQYSSIV M8 SEQ ID NO: 51 301-311 YSSIVDALSTK  F10 SEQ ID NO: 52 325-335 VSWYDNEWMY  F11 M9 SEQ ID NO: 53 337-341 CRCAD  M10

TABLE 8 The extent of sequence identity of the T. vaginalis GAPDH with the protein sequences of bacteria, yeasts, and human from alignment shown in FIGS. 3A, 3B, and 3C. Epitope F1 F2 F5 Organism M1 ALD32 M2 ALD30 M3 F3 F4 M4 M5 F6 T. vaginalis 100 100 100 100 100 100 100 100 100 100 T. suis 80 55 73 63 100 75 38 75 100 75 C. albicans 0 45 9 25 40 50 13 56 100 50 S. cerevisiae 0 45 9 13 60 50 13 56 100 63 C. trachomatis 0 55 0 0 60 50 13 67 100 50 T. pallidum 40 45 9 44 100 38 0 56 100 38 N. gonorrhoea 0 45 9 13 60 38 13 78 100 38 S. pneumoniae 0 55 9 25 40 38 25 67 80 38 S. pyogenes 0 55 9 25 20 38 25 67 80 63 S. aureus 0 45 0 25 60 38 13 56 100 75 E. coli 0 55 9 13 40 38 0 56 100 50 Homo sapiens 0 45 0 0 60 38 0 33 36 50 Epitope F7 F11 Organism B43 F8 M6 F9 M7 M8 F10 M9 M10 Overall T. vaginalis 100 100 100 100 100 100 100 100 100 100 T. suis 88 100 20 64 88 63 73 100 100 70 C. albicans 38 75 20 55 50 63 45 64 40 40 S. cerevisiae 38 75 20 64 63 50 45 64 40 39 C. trachomatis 38 75 20 55 88 75 55 55 40 38 T. pallidum 50 63 0 45 50 63 55 82 40 40 N. gonorrhoea 50 75 20 45 38 13 45 64 20 41 S. pneumoniae 63 75 20 18 75 38 55 73 0 40 S. pyogenes 63 75 20 27 75 38 55 73 0 40 S. aureus 50 88 20 55 38 25 55 73 40 40 E. coli 38 75 20 55 50 25 27 64 20 40 Homo sapiens 38 75 20 45 50 50 45 64 40 30

TABLE 9 Identification of epitopes of Trichomonas vaginalis (Tv) GAPDH reactive with human sera and MAbs and with identity to human and T. suis. % identity % identity unique Tv with with SPOTS amino female pooled epitope human T. suis peptide acid epitope patient reactive MAb for peptide peptide no. sequence sequence serum male sera reactions diagnosis sequence sequence SEQ ID NO: 36 3-5 13-17 LYPKD M1 + 80 SEQ ID NO: 37 12 34-44 YLLKYDTAHRA F1 ALD32C + 55 SEQ ID NO: 38 20 58-68 FTVGEGADKWV M2 + 73 SEQ ID NO: 39 23-24 70-77 KSIGGRLG F2 ALD30A + 63 SEQ ID NO: 139 25.27 79-83 SQLPW M3 60 100 SEQ ID NO: 40 31-33  94-101 STGIFRTK F3 + 75 SEQ ID NO: 41 35-37 106-113 AEGKIKKD F4 + 25 SEQ ID NO: 42 39-41 118-125 HLVSGAKK F5 M4 75 SEQ ID NO: 43 51-53 157-161 SNASC M5 50 100 SEQ ID NO: 44 57-59 175-182 NAFGIRNG F6 50 75 SEQ ID NO: 45 67-69 205-212 RRARAAGM F7 B43 88 SEQ ID NO: 46 72-74 217-224 TSTGAAIA F8 75 100 SEQ ID NO: 47 75-77 229-233 CHGLP M6 + 20 SEQ ID NO: 48 84 250-260 SLVDLTVNVNA F9 + 64 SEQ ID NO: 49 97-98 292-299 VSSDIIGC M7 50 88 SEQ ID NO: 50  99-100 298-305 GCQYSSIV M8 50 63 SEQ ID NO: 51 101  301-311 YSSIVDALSTK  F10 + 73 SEQ ID NO: 52 109  325-335 VLSWYDNEWMY  F11 M9 64 100 SEQ ID NO: 53 111-113 337-341 CRCAD  M10 + 100

TABLE 10 Identification of T. vaginalis (Tv) GAPDH peptide epitopes that have high sequence identity to GAPDH of and are diagnostic for Tritrichomonas suis (Ts). Only peptide epitopes of T. vaginalis with ≥50% identity were selected. no. amino Ts acid percent sequence (Tv) epitope sequence SEQ ID NO: (Ts) epitope sequence identity SEQ ID NO: 36 13-17 LYPKD 54 LYPKE 80 SEQ ID NO: 37 34-44 YLLKYDTAHRA 55 HLLNYDSAHQR 55 SEQ ID NO: 38 58-68 FFVGEGADKWV 56 FEVGTGSDKWV 73 SEQ ID NO: 39 70-77 KSIGGRLG 57 KNLTGRLG 62.5 SEQ ID NO: 40  94-101 STGIFRTK 58 STGLFRTH 75 SEQ ID NO: 41 118-125 HLVSGAKK 59 HLLAGAKK 75 SEQ ID NO: 43 157-161 SNASC 60 SNASC 100 SEQ ID NO: 140 172-179 TLNNAFGI 61 VLNDTFG1 57 SEQ ID NO: 141 202-212 KDLRRARAAGM 62 RRARAAGM 100 SEQ ID NO: 142 247-257 ITGSLVDLTVN 63 ITGSLVDITVN 91 SEQ ID NO: 51 301-311 YSSIVDALSTKV 64 HSSIVDSLSTMV 75 SEQ ID NO: 143 322-329 LVKVLSWY 65 LVKVLSWY 100

Additional noteworthy evidence of the GAPDH crossreactivity between T. vaginalis and T. suis (T. foetus) is evidenced by data obtained by detection on nitrocellulose of the T. foetus GAPDH after SDS-PAGE and immunoblotting of total proteins of different T. foetus isolates. The MAbs generated to the T. vaginalis GAPDH (Table 1) were used as probes to detect the T. foetus protein.

Example 7. Identification of Diagnostic Immunogenic Epitopes of α-Actinin Unique to Trichomonas vaginalis

TABLE 11 Identification of diagnostic immunogenic epitopes of α-actinin protein unique to T. vaginalis (Tv) amino woman reactive SPOTS acid epitope patient men unique numbers sequence name sequence serum serum MAb to Tv SEQ ID NO: 66  2  4-14 ACT1 RREGLLDDAWE F1 + SEQ ID NO: 67 11-12 34-41 ACT2 IQFETIET F2 + SEQ ID NO: 68 21-23 67-71 ACT3 KQPKM F3 + SEQ ID NO: 69 50 148-158 ACT4 YEHVAVNNFIT F4 + SEQ ID NO: 70 69 205-215 ACT5 YVYLDPEDVID F5 + SEQ ID NO: 71 80-82 244-248 ACT6 ADKIK F6 + SEQ ID NO: 72 97-99 295-302 ACT7 RGKLASVI F7 + SEQ ID NO: 73 111-112 334-341 ACT8 NRPIPEIP F8 + SEQ ID NO: 74 152-153 457-464 ACT9 HHSQLITY F9 M1 + SEQ ID NO: 75 165-166 496-503 ACT10 YDEAIAFK F10 M2 + SEQ ID NO: 76 214-216 646-650 ACT11 KLNYK F11 M3 + SEQ ID NO: 77 215-217 649-653 ACT12 YKVTY F12 M4 HA423 + SEQ ID NO: 78 268-270 808-812 ACT13 KYFDK F13 M5 +

TABLE 12 The extent of sequence identity of the T. vaginalis α-actinin with the protein sequences of bacteria, yeasts, and human. C. Epitope T. suis albicans S. cerevisiae HuACTN1 ACT-F1 (W1) 9 9 11 21 ACT-F2 (W2) 0 0 0 50 ACT-F3 (W3) 0 20 20 40 ACT-F4 (W4) 9 18 9 46 ACT-F5 (W5) 0 18 0 36 ACT-F6 (W6) 14 14 20 40 ACT-F7 (W7) 0 0 13 25 ACT-F8 (W8) 0 0 25 38 ACT-F1/M1 (W9/M1) 11 22 11 13 ACT-F10/M2 (W10/M2) 0 0 13 13 ACT-F11/M3 (W11/M3) 20 0 20 20 ACT-F12/M4 20 20 20 0 (W12/M4/HA423) ACT-F13/M5 (W13/M5) 0 20 0 40 Note absence of sequence identity with all proteins for representative organisms shown in Table 12. There is no identity of epitopes with other proteins of bacteria, fungi, protists, and humans in databanks.

Example 8. Synthesis of 15-Mer Peptide Epitopes of ALD, ENO, GAP, and ACT Unique to Trichomonas vaginalis to Demonstrate Immunoreactivity with Women and Men Sera

Based examination of the sequences with algorithms for hydrophobicity and antigenicity, we then selected 7 epitopes for ALD, 8 for ENO, and 6 for GAP, and the 13 for ACT (taken from Table 11) for synthesis of 15-mer peptides encoding the epitopes. Table 13 shows the epitopes and includes 3 for ACT to which data are presented below. The individual amino acid sequence encoding the epitope within each 15-mer peptide is shown in bold and underlined.

Peptide epitopes from each protein were selected based on low percent identity and solubility. The 15-mer amino acid sequences were sent to Sigma-Aldrich (The Woodlands, Tex.) and synthesized using their Custom PepScreen Peptide service. Each individual 15-mer peptide contained was acetylated at the amino-terminus and was amidylated at the carboxy-terminus. Each 15-mer peptide was screened by mass spectrometry to determine yield and purity of each product. Peptide epitopes were received with a pass/fail designation and the amount provided. Three α-actinin 15-mer peptides of ACT were used as positive controls in the experiments presented below. These peptides were designated ACT2, ACT3, and ACT1 and corresponded to the amino acid sequences AQPLYDEAIAFKEEV (SEQ ID NO:101), FKDTFKYFDKDKSNS (SEQ ID NO:102) and SVNRHHSQLITYIKH (SEQ ID NO:100), respectively (shown in Table 13).

TABLE 13 List of synthetic 15-mer peptides of representative epitopes of ALD, ENO, GAP, and ACT for reactivity with immunoreactive women and men sera. women/men epitope peptide amino acid designation name numbers amino acid sequence SEQ ID NO: 79 A-W1 ALD1 36-50 EQLQ AIITASVK TES SEQ ID NO: 80 A-ALD12 ALD2 138-152 EAHS RPDYVTVE GEL SEQ ID NO: 81 A-ALD64 ALD3 159-173 EDDVKAE KHTYTRPE SEQ ID NO: 82 A-W4 ALD4 167-181 HT YTRPEEVODFV SK SEQ ID NO: 83 A-W6 ALD5 230-244 SS SIPQEYVEMVN KY SEQ ID NO: 84 A-M2 ALD6 275-289 DG RMVMTGTIRRL FV SEQ ID NO: 85 A-W8 ALD7 301-315 LGEA RTKLTEM YMRK SEQ ID NO: 86 E-W1 ENO1 57-71 VK YLGRVTLA ARSSA SEQ ID NO: 87 E-M1 ENO2 70-84 VT LAARSSAP SGAST SEQ ID NO: 88 E-W3, E-M3 ENO3 136-150 TDG TVLKKNIG GNAC SEQ ID NO: 89 E-F4/M4 ENO4 182-196 DK VPKKFKLPSPF FN SEQ ID NO: 90 E-W5 ENO5 236-250 KL GGLLVKKY GLSAK SEQ ID NO: 91 E-M8 ENO6 295-309 SSE FYDEEKKL YEVE SEQ ID NO: 92 E-W7/M9 ENO7 344-358 DY ENWTKLNARLG QR SEQ ID NO: 93 E-W8, E-M10 ENO8 366-380 LYTT NPITIKKG LEG SEQ ID NO: 94 G-M1 GAP1  8-22 RACRK LYPKD IQVVA SEQ ID NO: 95 G-M2 GAP2 56-70 QE FTVGEGADKWV VK SEQ ID NO: 96 G-W2 GAP3 67-81 WVV KSIGGRLG PSQL SEQ ID NO: 97 G-W4 GAP4 104-118 KD AEGKIKKD DGYDGH SEQ ID NO: 98 G-M6 GAP5 224-238 ALPKV CHGLP PKSLD SEQ ID NO: 99 G-M10 GAP6 332-346 EWMYS CRCAD IFHRL SEQ ID NO: 100 ACT-W9, M1 ACT1 463-467 SVNR HHSOLITY IKH SEQ ID NO: 101 ACT-W10, M2 ACT2 492-506 AQPL YDEAIAFK EEV SEQ ID NO: 102 ACT-W13, M5 ACT3 803-817 FKDTF KYFDK DKSNS

Approximately 1 μg of individual and/or a combination of synthetic peptides were dot-blotted onto a nitrocellulose membrane and allowed to air dry for 30 min at 37° C. These dot-blots were fit into individual wells of a 96-well microtiter ELISA plate. Then, 100 μl of 2% ELISA-grade BSA (Sigma-Aldrich, St. Louis, Mo.) in PBS (eBSA-PBS), pH 7.4, was added and incubated for 2 h at RT, after which 5 μl of a 1:1 dilution (v/v) of T. vaginalis negative- and positive-control women or men sera in PBS, pH 7.4, was added and incubated for 30 min at RT. The remainder of the procedure is as detailed above. Densitometric scans were produced using the ImageJ software (rsbweb.nih.gov/ij).

FIGS. 5A, 5B, 5C, and 5D present results from representative dot-blot reactions using positive control sera of women and men of 15-mer peptides for ALD (1a and 1b), ENO (2a and 2b), GAP (3a and 3b), and ACT (4a and 4b) as a positive control (XX). Reactivity was detected for each 15-mer peptide, albeit at different levels of spot intensities. No peptides were detectable using negative control sera for both women and men that were determined to be unreactive with the full-length proteins. These data suggest that some peptide-epitopes have potential as serodiagnostic targets.

We next wanted to perform dot-blots (FIG. 6A) using random combinations of the 15-mer peptides to determine whether an increased extent of reactivity was seen for women and men sera. We further wanted combinations of peptides that might give equal reactivity for both sera. FIG. 6B presents in duplicate the intensity of signal for each combination with the positive control women and men sera (labeled 4+/5+), and no detection of the peptide cocktails was evident with negative control sera (labeled -0-). Densitometric scan (bars 1 through 7) revealed overall better extent of reactions with combination of peptides compared to the individual peptides for both women and men sera (data not shown). The combined peptides ACT2 and ACT3 (bars 8) served as positive controls with known sera of men and women reactive with α-actinin, and the pooled peptides GAP1, GAP6 and ENO3 (bars 9) as well as GAP5, ENO5, and ALD6 (bars 10) showed no reactivity with negative control sera of both women and men sera.

Example 8. Identification of Immunogenic Epitopes of α-Enolase and GAPDH with High Sequence Identity to Human Protein Sequences

From Tables 6 and 9 it was possible to identify three epitopes of α-enolase and one epitope of GAPDH with 62.5% to 78% identity to the human peptide sequences, as illustrated in Table 14. The peptide sequences were considered high identity if there was a difference in sequence by only two to three amino acids in an eight to nine linear amino acid sequence.

TABLE 14 Identification of Trichomonas vaginalis (Tv) peptide epitopes with high sequence identity to human (Hu) protein epitopes and with possible immune crossreactivity. amino female male acid patient sera patient sera MAb identity protein sequence epitope sequence reaction reaction reactivity (%) SEQ ID NO: 25 ENO  94-101 (Tv) DKARYGGK + + 78 SEQ ID NO: 103 (Hu) DKQRYLGK SEQ ID NO: 29 ENO 245-252 (Tv) KYGLSAKN + 62.5 SEQ ID NO: 104 (Hu) KYGKDATN SEQ ID NO: 4 ENO 364-371 (Tv) DDLYTTNP + 75 SEQ ID NO: 105 (Hu) DDLTVTNP SEQ ID NO: 144 GAP 322-329 (Tv) LVKVLSWY + + 62.5 SEQ ID NO: 106 (Hu) FVKLISWY

Example 9. Production of Recombinant Protein Encoding Sequential Epitope Sequences of Aldolase, GAPDH, α-Enolase, and α-Actinin Separated by Amino Acid Spacers for Use in Serodiagnosis

In this example, the epitopes identified in Tables 2-11 that are immunoreactive with seropositive sera of women and men for the proteins aldolase, GAPDH, α-enolase, and α-actinin are encoded within a plasmid construct so that the individual epitopes are within 15-mer peptides of the trichomonad protein. The epitopes may be in any random order so that, for example, the sequence of epitopes may include one for aldolase followed by one for α-actinin followed by one for α-enolase followed by one for aldolase, etcetera. Further, the number of epitopes may be just one each representative of each protein or as many as deemed necessary for each protein for optimal antibody detection in a serodiagnostic. The plasmid construct is then expressed in recombinant E. coli, and a recombinant protein is then made upon induction. This type of recombinant protein containing a series or an array of epitopes is referred to here as a String of Pearls (SOP) where each “pearl” is representative of the amino acid sequence within which is found an epitope as described. This recombinant protein can also be referred to interchangeably as a SOE or rSOE.

FIG. 7A presents a simple example of an SOP encoding sequentially two epitopes of GAPDH, two epitopes of α-enolase, and two epitopes of aldolase. The sequences of these individual epitopes and 15-mer epitopes are among those listed in Table 13 above. The SOP sequence identity is also provided in SEQ ID NO:145. This and other recombinant SOP arrays of epitopes of the T. vaginalis proteins aldolase, GAPDH, α-enolase, and α-actinin purified similarly can then be immobilized on surfaces for probing and detection by immunoreactive sera of women and men. FIG. 7B shows purification of an SOP, with lysate, flow-through, washes, and elution fractions in SDS-PAGE gel with Coomassie-brilliant blue stain.

The SOP encoding for an array of six 15-mer amino acid sequences, two each of which contained epitopes for ALD, ENO, and GAP was 111 amino acids for an Mr of 13.35-kDa. The DNA encoding for the SOP with a His₆ tag at the carboxy terminus was cloned into a pET23b expression plasmid construct that was transformed into E. coli B121DE3. Recombinant E. coli (rE. coli) was stored as glycerol stocks at −70° C. until used, which were thawed and streaked onto Luria Broth (LB) agar plates containing 25 μg ampicillin (amp). Isolated colonies were inoculated into 200 ml fresh LB containing amp and incubated in a shaker incubator at 37° C. and 220 rpm. Following overnight growth, rE. coli were inoculated into fresh LB medium with amp and incubated for 3 h at 37° C. at 220 rpm prior to addition of 1 mM IPTG and incubation an additional 3 h. The rE. coli were centrifuged using a Sorvall SLA-1500 rotor at 8,000 rpm and 4° C. for 15 min. Supernatant was decanted, and the pellet was stored at −80° C. until used. At various time intervals, prior to and after IPTG addition, 1 ml of rE. coli were microfuged at 10,000 rpm for 15 min and pellets prepared for SDS-PAGE (34, 35) for analysis of recombinant SOP::His₆ fusion protein (12.2-kDa) expression after IPTG addition. Immunoblot analysis after SDS-PAGE, shown in FIG. 8, confirmed the synthesis of SOP::His₆ using as probe positive control sera of women and men that were seropositive to α-actinin as defined above.

ELISA was performed by immobilizing purified SOP protein onto 96-well, flat-bottom Nunc polysterene plates. Each well was coated with 100 μl containing 1 μg of SOP diluted in carbonate:bicarbonate buffer, pH 9.6, and the plates were incubated o/n at RT with gentle agitation. Each plate was then washed 3× with PBS-T. On the third wash the plates were incubated in PBS-T for 5 min at RT with gentle agitation prior to removing the PBS-T. The plates were then incubated upside down o/n on at RT on paper towels before being covered with plastic wrap and stored at 4° C. until used. For testing, plates were washed twice with PBS-T. On the second wash the plates were incubated in PBS-T at RT for 5 min with gentle agitation and slap-dried. Each well was then blocked with 200 μl of eBSA-PBS for 2 h at 37° C. Plates were then washed twice with PBS-T. On the second wash the plates were incubated in PBS-T at RT for 5 min with gentle agitation followed by removing the PBS-T. Next, 100 μl of a 1:25 dilution in eBSA-PBS of women and men sera was added to each well in duplicate and incubated at RT for 5 min with gentle agitation before incubation for 4 h at 37° C. The plates were washed three times with PBS-T. On the third wash the plates were incubated in PBS-T for 5 min at RT with gentle agitation. After removal of the PBS-T, 100 μl of secondary horseradish peroxidase-conjugated goat-anti-human IgG (Fc-specific) diluted 1:1,500 in eBSA-PBS was added to each well and incubated at RT with gentle agitation for 5 min before incubation for 1 h at 37° C. The plates were washed 3× with PBS-T, as above, prior to addition of 100 μl of color development solution, prepared according to the manufacturer's instructions well and incubated at RT with gentle agitation for 15 min. Absorbance values at 405-nm were obtained using Bio-Tek plate reader (Bio-Tek Instruments, Inc).

We performed assays to assess whether this novel recombinant protein is detectable with positive control sera of women and men, as above. FIG. 8A shows representative reactions by ELISA with SOP arrays immobilized onto individual wells of 96-well microtiter plates. Negative control sera of women and men had little to no reactivity as evidenced by low A_(405 nm) with the SOP in comparison to the strong signals (high A_(405 nm)) obtained with positive sera of women and men. The SOP was undetectable when using an irrelevant MAb HA423 to α-actinin of T. vaginalis (XX) compared to the very strong reaction seen with a positive control MAb to hexa-histidine in the fusion recombinant protein.

Further, FIGS. 8B and 8C demonstrates that antibodies in positive sera of women and men react with the SOP array and are detected by dot-blots (FIG. 8B) and by immunoblot after SDS-PAGE and immunoblotting onto nitrocellulose (FIG. 8C). The Coomassie-brilliant blue stained gel is a duplicate from the SDS-PAGE used for immunoblotting of the SOP, and the Ponceau S-stained nitrocellulose is a duplicate included to show the transfer of the SOP protein onto nitrocellulose.

Example 9. Epitopes of Highly Immunogenic T. vaginalis α-Actinin Used as Serodiagnostic Targets for Both Women and Men

Highly immunogenic α-actinin protein and protein fragments were characterized to further establish utility as a target for serodiagnosis of trichomonosis for both women and men. It is known that the sera of women with trichomonosis possess antibody reactive with numerous trichomonad proteins, including α-actinin (referred to as positive control women sera). Epitope mapping identified 13 peptide epitopes within α-actinin reactive to the positive control sera of women. Men sera highly-seropositive to the trichomonad parent α-actinin and the truncated version called ACT-P2 (positive control men sera) identified 5 epitopes that were a subset of those detected by positive control women sera. The amino acid sequences of the epitopes had little or no sequence identity to the human α-actinin homolog and to proteins of other microbial pathogens, including a related Tritrichomonas suis and yeasts Candida albicans and Saccharomyces cerevisiae. Further, immobilized 15-mer peptides of representative epitopes are reactive to both positive control women and men sera.

A plasmid was constructed to encode an SOP array of all thirteen epitopes of α-actinin as shown in FIG. 9 (SEQ ID NO:146). This actinin SOP is expressed in E. coli as is the SOP presented above expressing epitopes of ALD, ENO, and GAP. In this case, the thirteen epitopes detected antibodies in the sera of women and men exposed to T. vaginalis are arranged sequentially within individual 15-mer peptides, which were separated from each other by a diglycine (-GG-). recombinant E. coli with the plasmid construct with the DNA sequence encoding this recombinant SOP of α-actinin is induced for expression of the protein. The α-actinin epitope protein is a fusion protein with a hexa-histidine sequence at the carboxy-terminus for purification as above by nickel-affinity chromatography. Purified α-actinin SOP can be immobilized for detection antibodies in the sera of women and men.

Materials and Methods

α-Actinin-P2 (ACT-P2) expression and purification.

The natural T. vaginalis α-actinin protein consists of 931-amino acids and is 106.2-kDa. This full-length highly immunogenic protein is used for examining the relation between seropositivity in men and prostate cancer. Subclones of the trichomonad α-actinin gene are made to determine the region of the protein most reactive with men sera. This subclone encoded a protein of 558-amino acid protein from the amino terminus, called ACT-P2. The coding region of ACT-P2 corresponding to amino acids 375 to 932 is PCR amplified and cloned in pET23b expression vector with the kanamycin resistance gene (Kan′) for transformation of E. coli BL21DE3 cells. The resulting recombinant 558-amino acid sequence further comprises a C-terminal His₆ tag fusion protein of 63.5-kDa. Bacteria are grown on Luria Broth (LB) agar plates containing 25 μg/ml Kan, and rE. coli is incubated for 3 h at 37° C. at 220 rpm prior to addition of 1 mM isopropylthiogalactoside and incubated for an additional 3 h. The rE. coli are centrifuged using a Sorvall SLA-1500 rotor at 8,000 rpm and 4° C. for 15 min. and pellets stored at −80° C. until used. Synthesis of ACT-P2 is confirmed using as probe the murine monoclonal antibody (MAb) HA423 (27-29) to trichomonad α-actinin or MAb to His₆ (Advanced Targeting Systems, San Diego, Calif., USA).

For purification of ACT-P2, pellets of rE. coli are thawed for 15 min on ice and suspended in 10-ml lysis buffer (50 mM Tris, pH 8.0, 300 mM NaCl, 10 mM β-mercaptoethanol (β-ME), and 0.1% Triton-X100), and lysates are sonicated 10 times each at room temperature (RT) for 30 seconds (sec). Sonicates are centrifuged using a Sorvall SS-34 rotor at 8,000 rpm and 4° C. for 20 minutes (min), and supernatant is applied to a Ni²⁺-NTA superflow affinity column according to the manufacturer's instructions (Qiagen Inc., Valencia, Calif., USA). Purified ACT-P2 protein is confirmed by SDS-PAGE and immunoblot using as probe MAb HA423, as above.

The Human ACTN1 Homolog.

The purified full-length human ACTN1 α-actinin homolog used in this study is the isoform B protein of 892 amino acids (˜103-kDa) (Novus Biologicals, Littleton, Colo., USA). The soluble protein is in 74 mM Tris-HCl, pH 8.0, containing 10 mM reduced glutathione. For ELISA and immunoblot assays 1 μg of ACT-P2 and ACTN1 is used. ELISA is performed using wells of microtiter plates coated with ACT-P2 or ACTN1 as detailed below. SDS-PAGE for immunoblotting onto nitrocellulose for both ACT-P2 and ACTN1 is carried out using 7.5% acrylamide gels, as before (36, 37).

Positive Control Sera of Women and Men and Detection of Antibody to ACT-P2.

During the course of our research on T. vaginalis we have examined ˜1,000 sera of women patients with trichomonosis and, more recently, up to 20,000 sera of men for seropositivity to trichomonad proteins and particularly α-actinin. We, therefore, were able to determine the extent of serum antibody to total T. vaginalis proteins, α-actinin, and ACT-P2 by ELISA (27-29). Individual, α-actinin-seropositive sera of women and men had identical or very similar reactivities to trichomonad proteins and α-actinin. This permitted us to pool the sera to have sufficient amounts for conducting epitope mapping experiments, as outlined below, and was considered positive control sera. Likewise, pooled seronegative sera of both women and men were considered negative control sera for parallel experiments conducted throughout.

Trichomonad Natural α-Actinin SPOTs Membrane Synthesis for Epitope Mapping.

Oligopeptides derived from the sequences of T. vaginalis α-actinin (GenBank accession number AAC72899) were synthesized on activated membranes using the SPOTs system (Sigma-Genosys, The Woodlands, Tex., USA). Five to 10 nmol of each peptide was covalently bound to a Whatman 50 cellulose support (Whatman, Maidstone, England) by the C-terminus using Fmoc-L amino acid chemistry and had an acetylated N-terminus. The oligopeptides were 11-mer amino acids in length and had a sequential overlap of eight amino acids. The SPOTs spanned the entire sequence of the protein.

Probing the α-Actinin SPOTs Membrane with Positive and Negative Control Sera and MAb HA423.

The membrane was initially washed with a small volume of 100% MeOH for 5 min to avoid precipitation of hydrophobic peptides during the following procedure. After washing 3× each for 10 min in 25 ml of TBS buffer (50 mM Tris-HCl, pH 8.0, 137 mM NaCl, and 2.7 mM KCl), the SPOTs membrane was incubated in Blocking Buffer (TBS containing 5% BSA) at RT for 2 h. The membrane was incubated with a 1:10 dilution of negative or positive control sera of women and men, respectively, and incubated o/n at 4° C. The membrane was also probed with the MAb HA423 that detects α-actinin. After washing 3× each for 5 min each in TBS, the membrane was incubated with a 1:1,500 dilution of secondary anti-human antibody as above or anti-mouse IgG Fab (IgG fraction) prepared in Blocking Buffer. After washing 3× each in TBS at RT for 5 min each, bound antibodies were detected using color development reagent.

Immediately following color development and SPOT analysis, the membrane was regenerated by washing 3× with water with each wash for 10 min at RT with agitation.

Bound antibody was stripped from the membrane by washing at least 4 times with each wash for 30 min with Regeneration Buffer I (62.5 mM Tris-HCl, pH 6.7, 2% SDS, and 100 mM β-ME) at 50° C. with agitation. The membrane was washed three times each for 20 min with 10× PBS at RT with agitation, after which the membrane was washed 3× each for 20 min with T-TBS buffer (TBS, pH 8.0, containing 0.05% Tween 20) at RT with agitation. This was followed by washing 3× each for 10 min with TBS at RT with agitation. The presence of any visible spots resulted in repeating the regeneration steps. As a control to show that the primary antibody was completely removed, the membrane was re-incubated with the appropriate secondary antibody and substrate solution and developed. Regeneration was continued until no reactivity was seen with secondary antibody.

The epitope amino acid sequences were determined based on reactivities of overlapping peptides, as shown above in Table 11. Epitope sequences were compared with other proteins by using the protein-protein basic local alignment search tool found on a page of the NCBI website. Amino acid sequence alignments of the proteins were performed with CLC Protein Workbench (Muehltal, Germany). Hydrophobicity plots and antigenicity plots were constructed using Lasergene MegAlign (DNASTAR, Madison, Wis.).

Synthesis and Reactivity of Individual α-Actinin Epitopes.

Three 15-mer peptide epitopes identified from SPOT membrane epitope mapping with low percent identity to other human pathogens as well as the α-actinin human homolog were synthesized in PEPscreen format (Sigma-Genosys). The reactivity of each peptide was tested with representative negative and positive control sera either individually or in combination. Approximately 10 μg of peptide was blotted onto nitrocellulose membranes and air dried o/n at RT. The epitope blots were then blocked with 2% e-BSA in PBS at 37 C for 2 h followed by incubation with 1:25 dilution in PBS of negative or positive control women and men sera for ACT-P2 and incubated o/n at RT. This was followed by secondary antibody and color development, as above. All assays were performed in duplicate and repeated at least three times.

Results

Positive Control Sera of Women and Men does not Detect the Human α-Actinin Homolog Protein.

Negative and positive control sera of women and men were used to probe immunoblots of ACT-P2. As can be seen in FIG. 10 positive (pos) control sera of women (lanes 3a and 3b) and of men (lanes 5a, and 5b) detected ACT-P2 in two separate experiments done at different times under identical experimental conditions. Negative (neg) control sera of women and of men gave no detectable bands (lanes 2 and 4, respectively). The IgG1 MAb HA423 to the trichomonad α-actinin used as probe gave strong reactivity in separate experiments (lanes 1 and 6), and, not unexpectedly, an irrelevant IgG₁ MAb B44 reactive with trichomonad α-enolase as a negative control detected no protein band.

We next tested for immuno-crossreactivity purified, commercially-available human α-actinin (HuACTN1) with pooled positive control sera of women and men used in FIG. 10. FIG. 11A (lane 5) shows the intense stained band of 1 μg HuACTN1. Gels with the same amount of HuACTN1 were transferred onto nitrocellulose for immunoblotting. A duplicate blot with HuACTN1 was stained to insure transfer of the protein (not shown). The HuACTN1 was neither detected by the positive control sera (lane 4) nor HA423 (not shown). As above, 1 μg of ACT-P2 (lane 3) was readily detected by MAb HA423 (lane 1) and rabbit antiserum to total T. vaginalis proteins (IRS, lane 2). We then tested by immunoblot using total proteins of T. vaginalis (lane 10), as before, whether the pooled positive control sera of both women and men detected numerous other trichomonad proteins. FIG. 11B shows that pooled negative control sera did not detect any trichomonad proteins by immunoblot (lane 7) whereas pooled positive control sera recognized numerous proteins (lane 8). As a control and not surprisingly, many trichomonad proteins in the total protein preparation were evident when blots were probed with IRS (lane 9). As with negative control sera of women and men (lane 7), no proteins were detected by control, prebleed normal rabbit serum. Finally, we tested for detection of non-denatured HuACTN1 coated onto wells of microtiter plates. Again, neither positive control sera of women and men nor MAb HA423 reacted to the HuACTN1-coated wells (not shown).

α-Actinin Epitopes React with Positive Control Sera of Women and Men and MAb HA423.

We next tested the positive control sera of women and men strongly reactive with ACT-P2 for IgG antibody to overlapping 11-mer peptides on a Custom SPOTs membrane (Materials and Methods). Table 5A of Example 7 lists the 13 epitopes and corresponding amino acid sequences labeled W1 through W13 recognized by women sera. M1 through M5 represent the subset of epitopes detected by men sera. The IgG₁ MAb HA423 detected the same epitope as W12/M4. Negative control sera of women and men and the MAbs B43 and B44 to trichomonad GAPDH and α-enolase, respectively, which were the same isotype as HA423, were unreactive with the SPOTs membrane.

FIG. 12A shows a representative reaction for epitope detection of 11-mer overlapping peptides (SEQ ID NO:162-165) for spots numbered 214 through 217. The highly reactive SPOTs 214 through 217 for positive control sera of women indicates the epitope sequence of 643-VEFKLNYKVTY-653 (SEQ ID NO:163). (FIG. 12B). Likewise, the 216 and 217 peptides reactive with positive control sera of men suggest the sequence 649-YKVTYS-653 as the epitope. No reactivity was seen with negative control sera of either women or men. The MAb HA423 epitope is 643-VEFKLNYKVTY-653 (SEQ ID NO:163). FIG. 12C shows the strong dot-blot reaction by positive control sera of women and men to ACT-P2 immobilized on nitrocellulose. We then synthesized 15-mer peptides overlapping W10/M2 (AQPLYDEAIAFKEEV) (SEQ ID NO:101) and W13/M5 (FKDTFKYFDKDKSNS) (SEQ ID NO:102), epitopes from Table 11 (epitopes underlined), and immobilized 1 μg of each peptide together and probed with positive control sera. The sera of both women and men reacted with the combined 15-mer peptide epitopes (FIG. 12D). FIG. 12E presents densitometric scans of the reactive spots and shows the elevated level of detection by men sera compared to women sera. Finally, FIG. 12F shows the reactivity of individual 15-mer peptides containing the epitopes of W9/M1 (SVNRHHSOLITYIKH) (SEQ ID NO:100), W10/M2, and W13/M5 with positive control sera. FIG. 12G illustrates the densitometric scans that show men sera giving elevated intensities to W9/M1 and W10/M2 compared to women sera. The extent of detection was identical for both sera of women and men to the epitope W13/M5. Negative control sera of both women and men showed no reactions in these dot-blots of epitopes.

Hydrophobicity and Antigenicity Profiles of the Natural α-Actinin Sequence.

We then analyzed the immunoreactive epitopes of Table 11 for hydrophobicity and antigenicity. FIG. 13 demonstrates the mapping of the epitopes with the respective profiles and shows that most epitopes were hydrophilic and corresponded with predicted antigenicity. As representative examples, epitopes W3, W4, W8, HA423/M4/W12, and M5/W13 each gave prominent hydrophilic and antigenic characteristics that were not inconsistent with serum antibody detection.

Sequence Alignment of the T. vaginalis α-Actinin with Proteins of Other Representative Organisms and of the HuACTN1.

BLAST of T. vaginalis α-actinin amino acid sequence (SEQ ID NO:157) is presented in FIGS. 14A, 14B, 14C, and 14D and shows little amino acid percent identity with α-actinin-like proteins of different species. The low percent identity of amino acids is particularly noteworthy for the boxed epitope sequences indicated above the T. vaginalis amino acid sequence detected by both positive control sera of women and men. Table 12 summarizes the percent amino acid sequence identity comparisons for the individual epitopes compared with sequences for T. suis, a related trichomonad, and the yeasts C. albicans, and S. cerevisiae.

The organisms shown in FIGS. 14A, 14B, 14C, and 14D and Table 12 were chosen because of their relation to STIs and/or eukaryotic pathogens. The range of amino acid percent identity was from 0% to 25%. The percent amino acid identity for α-actinin of T. vaginalis compared with the HuACTN1 was 0% to 50%. Not unexpectedly, the seemingly high percent sequence identity of any epitope with the corresponding region of HuACTN1 decreased when neighboring amino acids were analyzed. Specific synthesized peptide epitopes of α-actinin with low to no amino acid sequence identity with other proteins were reactive with positive control sera of both women and men, as shown for representative epitopes in FIG. 12.

Discussion

Research in our laboratory led to the development of the lateral flow, immunochromatographic diagnostic for detection of trichomonad protein in female patients, and this diagnostic was commercialized and is currently in use in the United States and other countries (OSOM® Trichomonas Rapid Test, Sekisui Diagnostics, San Diego, Calif.). This diagnostic, developed in our laboratory, works on neither urine nor secretions obtained from male patients nor on urine spiked with lysates of total T. vaginalis proteins based on our analysis in the laboratory. Reports suggesting a relation between seropositivity to the ACT-P2 of T. vaginalis and prostate cancer reveal the need for a serum-based point-of-care diagnostic that utilizes a highly specific target. Our data show that the 558-amino acid ACT-P2 is a good target for detection of antibody in both women and men seropositive to T. vaginalis. This region of ACT-P2 was found to possess less homology with other α-actinin-related proteins, further reinforcing its diagnostic value. The fact that the epitopes detected by the positive control sera of men are located toward the C-terminus revealed why ACT-P2 was a good target for our earlier screening for serum antibody. It is noteworthy that there is absent or little identity between the peptide-epitope sequences with other proteins in databanks and among proteins for T. suis, C. albicans, and S. cerevisiae and the HuACTN1 of humans (Table 12 and FIGS. 14A, 14B, 14C, and 14D). This suggests strongly that high seropositivity is the result of exposure to T. vaginalis. Furthermore, of particular interest is that 15-mer synthetic peptide-epitopes found within ACT-P2 immobilized onto nitrocellulose were detected by sera of both positive control sera women and men reactive to α-actinin (FIG. 12). Perhaps not surprisingly, most of the peptide epitope amino acid sequences represented portions of the protein that were hydrophilic and antigenic (FIG. 4). The representative 15-mer synthetic peptides corresponding to W10/M2 and W13/M5 that were readily detected on immobilized surfaces were in fact highly hydrophilic (FIG. 12). This further suggests that the reactive 15-mer epitopes represent linear, readily detectable epitopes. A cocktail of or a recombinant protein encoding for a series of highly-reactive epitopes, such as a rSOE or SOP, represents diagnostic targets.

It is not surprising that α-actinin represents a target for serodiagnostic. This is one of the most immunogenic proteins of T. vaginalis. Its function is to associate with actin, which is important because of the dramatic and rapid morphologic transformation that this organism undergoes immediately following contact with vaginal epithelial cells, prostate epithelial cells (unpublished data), and extracellular matrix proteins, such as laminin and fibronectin. Indeed, recent transcriptomic and proteomic analyses has revealed the dramatic increased expression levels of α-actinin required for cytoskeletal rearrangements for morphological changes upon adherence to vaginal epithelial cells and binding to fibronectin. Further, equally elevated amounts of mRNA encoding for trichomonad GAPDH and α-enolase were found, and both of these proteins are surface ligands for binding fibronectin. There are four α-actinin human homologs, none of which are crossreactive with the MAb HA423 to the trichomonad α-actinin (FIG. 9 and Table 15) and with positive control sera of women and men. These human α-actinin proteins are known to have a less conserved central region, as is the case for all actin-binding proteins of the spectrin family.

Equally noteworthy is that the epitopes detected by MAb HA423 and positive control sera of women and men are invariant. Laboratory-adapted T. vaginalis isolates grown in batch culture for >20 years possess the MAb 423-immunoreactive α-actinin with the same M_(r). Further, more than fifty fresh clinical isolates, one-half of which are the Type II P270 phenotypically-varying isolates with the dsRNA virus, all possess α-actinin detected by MAb and positive control sera of women and men. We have seen no relation between T. vaginalis with or without mycoplasma and changes with α-actinin. Thus, this invariant and stable immunogenic protein appears suitable for a rapid serodiagnostic test for trichomonosis.

Of interest is the number of epitopes detected by the positive control sera of women patients compared to sera of men. This may be the result of different presentation of the protein(s) during immune surveillance that results from the unique urogenital regions of women in contrast to men. It is known to those of ordinary skill in the art that women patients with trichomonosis possess IgG antibody in the serum and vagina to numerous trichomonad proteins, perhaps indicating a more vigorous antibody response during infection compared to men. Studies by others demonstrated the highly immunogenic nature of and serum antibody response by women to α-actinin. Nonetheless, these data show that men respond to exposure to T. vaginalis by producing serum IgG antibody, especially to the epitopes located toward the carboxy-terminal region with the least identity to other known proteins. Importantly, what remains unknown is the temporal relationship between seropositivity with initial exposure to this STI, and this critical absence of clinical information perhaps may be corrected through future availability of a serodiagnostic for women and men. What is known, however, albeit in only a small sample size is that one week after treatment of women with trichomonosis the vaginal antibody to proteinases was not detected.

The literature is replete with examples of peptide epitopes utilized for diagnostics of infectious diseases. For example, rapid diagnostics for Plasmodium falciparum employ epitopes of histidine-rich proteins. Diagnosis of visceral leishmaniasis is performed with rapid antigen-based tests, and specific epitopes of the proteins p120 and p140 are used for detection of Ehrlichia chaffeensis and E. canis, respectively. This shows the value of characterization of immunogenic epitopes for developing specific targets for serodiagnosis. In summary, our results present evidence for the validity of α-actinin and the truncated ACT-P2 as a target for serodiagnosis in both women and men exposed to T. vaginalis. This is important not only for screening men possibly exposed to this STI in relation to the possibility of prostate cancer development but for a more rapid, non-invasive test for women as well. This approach highlights the methods by which peptide epitopes of immunogens may be identified as targets for antibody detection for determining exposure to and infection by this significant STD pathogen.

Example 10. A-Actinin String-of-Pearls (KK-ACT-SOP) Epitopes, and SOE Sequences

Sequences are shown in Table 15, comprising 229 amino acids; pI=9.93; MW=27,207 Da.

TABLE 15 T. vaginalis α-Actinin epitopes, and SOE sequences EPITOPE # EPITOPE NAME AA SEQUENCE SEQ ID NO: 107 1 W1 SV RREGLLDDAWE KT SEQ ID NO: 108 2 W 2 LARQ IQFETIET DFE SEQ ID NO: 109 3 W 3 PSKWH KQPKM MVQKR SEQ ID NO: 110 4 W 4 QG YEHVAVNNFTT SW SEQ ID NO: 111 5 W 5 GI YVYLDPEDVID TT SEQ ID NO: 112 6 W 6 KIAAM ADKIK RTVAI SEQ ID NO: 113 7 W 7 IPGI RGKLASVI SYN SEQ ID NO: 114 8 W 8 CKSG NRPIPEIP QGL SEQ ID NO: 100 9 W 9/M1 SVNR HHSQLITY IKH SEQ ID NO: 101 10 W 10/M2 AQPL YDEAIAFK EEV SEQ ID NO: 117 11 W 11/M3 ELVEF KLNYK VTYTY SEQ ID NO: 118 12 W 12/M4/HA423 EFKLN YKVTY TYSDA SEQ ID NO: 102 13 W 13/M5 FKDTF KYFDK DKSNS SEQ ID NO: 120 KK-SV RREGLLDDAWE KT-KK-LARQ IQFETEET DFE-KK- PSKWH KQPKM MVQKR-KK-QG YEHVAVNNFTT SW-KK- GI YVYLDPEDVID TT-KK-KIAAM ADKIK RTVAI-KK-IPGI RGKLASVI SYN- KK-CKSG NRPIPEIP QGL-KK-SVNR HHSQLITY IKH-KK- AQPL YDEAIAFK EEV-KK-ELVEF KLNYK VTYTY-KK-EFKLN YKVTY TYSDA- KK-FKDTF KYFDK DKSNS-KK-HHHHHH SEQ ID NO: 120 KKSV RREGLLDDAWE KTKKLARQ IQFETIET DFEKKPSKWH KQPKM MVQKR KKQG YEHVAVNNETT SWKKGI YVYLDPEDVID TTKKKIAAM ADKIK RTVAIK KIPGI RGKLASVI SYNKKCKSG NRPIPEIP QGLKKSVNR HHSQLITY IKHKKAQP L YDEAIAFK EEVKKELVEF KLNYK VTYTYKKEFKLN YKVTY TYSDAKKFKDT F KYFDK DKSNSKKHHHHHH SEQ ID NO: 12 KKSVRREGLLDDAWEKTKKLARQIQFETIETDFEKKPSKWHKQPKMMVQKRKK QGYEHVAVNNFTTSWKKGIYVYLDPEDVIDTTKKKIAAMADKIKRTVAIKKIPGIR GKLASVISYNKKCKSGNRPIPEIPQGLKKSVNRHHSQLITYIKHKKAQPLYDEMAF KEEVKKELVEFKLNYKVTYTYKKEFKLNYKVTYTYSDAKKEKDTFKYFDKDKSN SKKHHHHHH

Example 11. Examples of T. pallidum Highly Immunogenic Peptides, 15-Mer Epitopes, and SOE as Targets for Serodetection, Shown in Table 16

As taught by Brinkman, epitope sequences identified as SEQ ID NO:121-124 are highly immunogenic. Antoni teaches that the epitope sequence identified as SEQ ID NO:125 is highly immunogenic, and Liu teaches that sequences of SEQ ID NO:126 are also highly immunogenic. Additional immunogenic protein sequences for T. pallidum are provided in SEQ ID NO: 161-164. Based on this information, and using the methods of the invention, the SOE of SEQ ID NO:127 was designed and synthesized. Experimental evidence shows that it is able to detect T. pallidum in a biological sample, and to elicit an immune response when injected into a subject. The H₆ (also referred to as hexa-His) at the amino terminal end of the SOE polypeptide is for purification of the SOE using Ni-NTA (nickel) affinity chromatography.

TABLE 16 T. pallidum epitopes and SOE sequences AA SEQUENCE SEQ ID NO: 121 LSTSLLTTCDFTGIFA SEQ ID NO: 122 IQSEVPIK SEQ ID NO: 123 LLIGGSRGYGEIKLE SEQ ID NO: 124 RPDLYAAVGE SEQ ID NO: 125 ASGAKEEAEKKAAEQRALL SEQ ID NO: 126 EVEDVPKVVEPASEREGGER SEQ ID NO: 127 KK-LSTSLLTTCDFTGIFA-KK-IQSEVPIK-KK- LLIGGSRGYGEIKLE-KK-RPDLYAAVGE- KK-ASGAKEEAEKKAAEQRALL-KK- EVEDVPKVVEPASEREGGER-KK-HHHHHH

-   Brinkman, M B, et al., 2008. A novel Treponema pallidum antigen,     TP0136 . . . Infect. Immun. 76:1848-1857. -   Antoni, G., et al., 1996. Detection of antigen determinants in the     Treponema pallidum 189:137-140. -   Liu, H., et al., 2007. Molecular characterization and analysis of a     gene . . . 56:715-721.

Example 12. Examples of N. gonorrhoeae Highly Immunogenic Peptides, 15-Mer Epitopes, and SOE as Targets for Serodetection, Shown in Table 17

Epitope sequences, SEQ ID NO:128-133, were derived from Cooke et al., 1997; 143:1415-1422. Additional immunogenic protein sequence for N. gonorrhoeae is provided in SEQ ID NO:165. Based on this information, SOE with sequence provided in SEQ ID NO:134 was designed and synthesized. Experimental evidence shows that it is able to detect N. gonorrhoeae in a biological sample, and to elicit an immune response when injected into a subject. The H6 at the amino terminal end of the SOE polypeptide sequence is for purification of the SOE using Ni-NTA (nickel) affinity chromatography.

TABLE 17 N. gonorrhoeae highly immunogenic peptides encoded in 15-mer epitopes, and SOE. AA SEQUENCE SEQ ID NO: 128 FGSKIGFKGQEDLGN SEQ ID NO: 129 GFSGSVQYAPKDNSG SEQ ID NO: 130 GFFAQYAGLFQRYGE SEQ ID NO: 131 VEKLQVHRLVGGYDN SEQ ID NO: 132 NSHNSQTEVAATAAY SEQ ID NO: 133 NTYDQVVVGAEYDFS SEQ ID NO: 134 KK-FGSKIGFKGQEDLGN-KK- GFSGSVQYAPKDNSG-KK- GFFAQYAGLFQRYGE-KK- VEKLQVHRLVGGYDN-KK- NSHNSQTEVAATAAY-KK- NTYDQVVVGAEYDFS-KK-HHHHHH 

What is claimed is:
 1. A method for detecting the presence of one or more Trichomonas vaginalis microorganisms in a biological sample of a subject, comprising the steps of: combining said biological sample with a polypeptide including a series of epitopes (SOE) which includes at least a plurality of epitopes selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 44, SEQ ID NO:82, and SEQ ID NO: 137, said epitopes being arranged as a linear array with each of said epitopes being connected by an amino acid linker consisting of a repeat of an amino acid, wherein said combining is performed under conditions whereby antigen-antibody complexes are permitted to form; and detecting formation of at least one antigen-antibody complex as an indication of a presence of at least one microorganism of said one or more Trichomonas vaginalis microorganisms in said biological sample.
 2. The method of claim 1, wherein said Trichomonas vaginalis microrganisms are selected from the group consisting of T. vaginalis isolates T016, T068-II, UT40, and VB102.
 3. The method of claim 1, wherein said detecting step is performed using an immunoassay.
 4. The method of claim 3, wherein said immunoassay is an enzyme-linked immunosorbent assay (ELISA).
 5. The method of claim 1, wherein said biological sample is selected from the group consisting of serum, plasma, blood, saliva, semen, cerebrospinal fluid, semen, prostatic fluid, urine, sputum, joint fluid, body cavity fluid, whole cells, cell extracts, tissue, biopsy material, aspirates, exudates, vaginal washings, pap smear samples, pap smear preparations, slide preparations, fixed cells, and tissue sections.
 6. The method of claim 1, wherein said subject is selected from the group of human, non-human primate, dog, cat, cattle, sheep, swine, horse, bird, mouse and rat.
 7. A polypeptide including a series of epitopes (SOE) which includes at least a plurality of epitopes selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 44, SEQ ID NO:82, and SEQ ID NO: 137 said epitopes being arranged as a linear array with each of said epitopes being connected by an amino acid linker consisting of a repeat of an amino acid.
 8. A kit for detecting the presence of one or more Trichomonas vaginalis microorganisms comprising at least one polypeptide of claim 7 and assay reagents or media for detecting formation of at least one antigen-antibody complex comprising said at least one polypeptide.
 9. A method of eliciting an immune response to a Trichomonas vaginalis microorganism in a subject, comprising the steps of preparing a pharmaceutical composition comprising at least one SOE, which includes at least a plurality of epitopes selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 44, SEQ ID NO:82, and SEQ ID NO: 137, said epitopes being arranged as a linear array with each of said epitopes being connected by an amino acid linker consisting of a repeat of an amino acid , and a suitable carrier and adjuvant, and administering said pharmaceutical composition to said subject in an amount sufficient to stimulate formation of antibodies to said SOE by the immune system of said subject. 